Registered third-party commands

Automatic register third-party commands, this new feature allow extend console commands.
The developers can add your own commands, the modules must have this structure
```bash
$ ls MyModule/lib/Drupal/MyModule/Command/MyAwesomeCommand.php
$ ls MyModule/lib/Drupal/MyModule/Command/OtherCommand.php
$ ls MyModule/lib/Drupal/MyModule/Command/Section/EspecialCommand.php
```
The Command must have a ["Command"](https://github.com/hechoendrupal/DrupalAppConsole/pull/48/files#diff-e4c0481a4e0da076d5594a4b910a0c61R67) word in the name