Cleanup + console banner

Hej !

This PR just do a lot of cleanups (mainly missing docblock, some part of the code where the IDE was complaining, PSR-2 conventions...).

I also moved the Producer classes (AbstractProducer and ProducerInterface) to their own namespace, and added the AbstractJob classes.

Finally, I added some console banner so that it's clearer when you run php index.php, at least you know what to write ;-).

I'll wait this one to be merged before changing the config to unify it :).