Fix `Gitlab::Database::SchemaCacheWithRenamedTable` does not work with many databases

We use views to perform non-interruptive renamed of tables. Currently we inject SchemaCacheWithRenamedTable into make Rails look at a different table (under view). This does not work with many connections as we use ActiveRecord::Base.connection. Secondly, our different attempts to use connection did result in set of random failures and hacky solutions.

We should consider:

1. Removing that for time being (and consider bringing this back next)
2. Fixing