contrib: container images should also be tested with postgresql and mysql

[dmsimard]

What is the idea ?

We have mysql and postgresql integration test coverage support via the ara ansible collection which tests the server in various configurations.

However, when we build the container images, the tests we do are very minimal and only with the sqlite backend. This is quite optimistic and in fact lead to the release of images with broken support for mysql and postgresql (see https://github.com/ansible-community/ara/pull/410).

We should test the container images with a mysql and postgresql container similar to how we do it in ara-collection.