Rejig agnostic database configuration for CI
Rejig agnostic database configuration for CI

Prior to this change CI was attempting to connect to the postgres
database with the mysql user's credentials. This should ensure that
doesn't happen and the database agnosticism can work in CI and other
environments.

alphagov/signonotron2,alphagov/signonotron2,alphagov/signonotron2,alphagov/signonotron2