Making the username unique.
Providing a consistent means of creating unique users and roles.
Fixing test user creation.
Adding a user manager.
Ignoring code coverage for dependency injection extensions.
Being explicit with nullable expectations.
Updating Symfony framework and dependencies.
Removing excess whitespace.

Depending on how big this configuration file gets, I may come back later and start commenting on things. As it is right now, it is not that complicated.
Verifying that the username is unique.
Adding a user email address entity.
Fixing missing debugging query log.
Adding a method to create unique email entities.
Fixing indentation.
Fixing logger configuration.
Adding support for email addresses.

Also modified the other tests so that we can perform query count checking.