Issue:
[REFACTOR] Remove the `pii-encryption-script` cargo feature

### Description

As of now, the `sandbox` and `production` cargo features differ only by the `pii-encryption-script` cargo feature:

https://github.com/juspay/hyperswitch/blob/fc6acd04cb28f02a4f52ec77d8ae003957183ff2/crates/router/Cargo.toml#L19-L20

If we're to use a single Docker image for all our environments as described in #1346, then this would be an initial step towards that goal.

Resolution:
<think>
PR Context:
- Title: refactor(router): remove `pii-encryption-script` feature and use of timestamps for decryption
- Merged: 2023-06-05T13:37:30Z
- Files changed: 24 files
- Commits: 3 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This PR removes the `pii-encryption-script` cargo feature from the `router` crate, and the usage of timestamps to decide and decrypt data stored in the database.

### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This 
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** refactor(router): remove `pii-encryption-script` feature and use of timestamps for decryption (#1350
Files to modify:


**crates/router/src/bin/router.rs**
  Modify existing code

**crates/router/src/configs/defaults.rs**
  Modify existing code

**crates/router/src/configs/settings.rs**
  Modify existing code

**crates/router/src/core/customers.rs**
  Modify existing code

**crates/router/src/db.rs**
  Remove:
    - function: private::get_migration_timestamp
    - function: private::get_migration_timestamp

**crates/router/src/db/address.rs**
  Modify existing code

**crates/router/src/db/customers.rs**
  Modify existing code

**crates/router/src/db/merchant_account.rs**
  Modify existing code

**crates/router/src/db/merchant_connector_account.rs**
  Modify existing code

**crates/router/src/db/merchant_key_store.rs**
  Modify existing code

**crates/router/src/lib.rs**
  Remove:
    - mod: pub::scripts

**crates/router/src/scripts.rs**
  Remove:
    - mod: pub::pii_encryption

**crates/router/src/scripts/pii_encryption.rs**
  Remove:
    - function: pub::create_merchant_key_store
    - function: pub::encrypt_merchant_account_fields
    - function: pub::encrypt_merchant_connector_account_fields
    - function: pub::encrypt_customer_fields
    - function: pub::encrypt_address_fields
    - function: pub::test_2_step_encryption

**crates/router/src/services.rs**
  Modify existing code

**crates/router/src/types/domain/address.rs**
  Modify existing code

**crates/router/src/types/domain/behaviour.rs**
  Modify existing code

**crates/router/src/types/domain/customer.rs**
  Modify existing code

**crates/router/src/types/domain/merchant_account.rs**
  Modify existing code

**crates/router/src/types/domain/merchant_connector_account.rs**
  Modify existing code

**crates/router/src/types/domain/merchant_key_store.rs**
  Modify existing code

**crates/router/src/types/domain/types.rs**
  Modify existing code