Bump gds-api-adapters to get ContentStore
Refactor Finders to pull from content_store

This commit contains the work needed to pull Finders from the
content_store and removes the ability for Finders to be retrieved from
the content-api.

Finders and email-alert-subs now pull their content_item and the
relevant tests have been updated to stub the content_store.
Merge pull request #95 from alphagov/fetch-from-content-store

Fetch from content store