[3.0] Remove *.class parameters in bundles

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11881
| License       | MIT
| Doc PR        | none

Remove the *.class parameters in all bundle settings.

see: https://github.com/symfony/symfony/issues/11881
Currently, the `validator.class` parameter is modified [in the container extension](https://github.com/symfony/symfony/blob/master/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php#L755). You will have to change that to modify the service definition's class directly.