Add an auto_alias compiler pass

Discussion see https://github.com/symfony/symfony/issues/11460

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | [#11460]
| License       | MIT
| Doc PR        |
At least for the usecase of default backend services this is not the case. So for example the default implementation is written against any kind of SQL, but you want to use mysql specific optimizations.

You specify default_backend to by 'mysql' and piece by piece swap out services where you can
do a little bit better. In this case its intended to not have a corresponding service for all auto_alias services.