Replacement of the in-memory implementation of the replication jobs queue with Postgres

Currently we have an in-memory and a postgres implementation ReplicationJobQueue. In some cases they behave differently and well tested locally code which uses in-memory implementation may cause issues on the production where the postgres implementation is used.
As we already have a dependency on the postgres database for the test-with-postgres job it makes sense to use only postgres implementation in all our tests and remove in-memory implementation.