[FrameworkBundle] Adds the possibility to register Commands via the DIC

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | don't now
| Fixed tickets | #8166
| License       | MIT
| Doc PR        | symfony/symfony-docs#3031

Todo:

* [x] Documentation
* [x] Clean code (add type hinting)
* [x] Add tests