N+1 query on loading the subscriptions list

### Problem

Our `SubscriptionPresenter` produces too many extra queries when we call it. The presenter returns the state of EULA request by querying the `eula_requests` table.
The simplest fix would be including this table (`eula_requests`) to the list of subscriptions but the `Subscription` model is not the `ActiveRecord` class. We can't use `include` on it. We should find another way of preloading `eula_requests` for the given list of subscriptions.

```
web     |   EulaRequest Load (0.6ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00038997"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039203"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.3ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039203"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039214"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.5ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039214"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039215"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039215"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039217"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.3ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039217"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039218"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.6ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039218"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039257"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.3ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039257"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.3ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00038996"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00038996"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039210"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039210"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039205"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.3ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039205"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (2.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039208"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039208"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039211"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039211"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039213"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.3ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039213"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039202"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039202"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00038717"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   CACHE Order Load (0.0ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00038717"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00038717"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   CACHE Order Load (0.0ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00038717"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   Order Load (0.4ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039204"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039204"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039207"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039207"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00038720"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.4ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00038720"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:133
web     |   Order Load (0.5ms)  SELECT  "orders".* FROM "orders" WHERE "orders"."zuora_account_id" = $1 AND "orders"."subscription_name" = $2 ORDER BY "orders"."updated_at" DESC LIMIT $3  [["zuora_account_id", "2c92c0f872e0ce920172e660eb610357"], ["subscription_name", "A-S00039556"], ["LIMIT", 1]]
web     |   ↳ app/models/subscription.rb:40
web     |   EulaRequest Load (0.5ms)  SELECT  "eula_requests".* FROM "eula_requests" WHERE "eula_requests"."subscription_name" = $1 AND "eula_requests"."accepted_at" IS NULL LIMIT $2  [["subscription_name", "A-S00039556"], ["LIMIT", 1]]

```

Story points: 2.0