Add RabbitMQConsumerTotalProxy to lazy RabbitMQ services for messages

This is just a simple proxy because we can't lazy load RabbitMQ service just to count number of messages in the queue.
As they are automatically injected in the controller now, we can't lazy load them.

Also forgot to use `AbstractController` in previous PR about _controller as a service_.

src/Wallabag/CoreBundle/Controller/StaticController.php

@@ -2,10 +2,10 @@
 
 namespace Wallabag\CoreBundle\Controller;
 
-use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\Routing\Annotation\Route;
 
-class StaticController extends Controller
+class StaticController extends AbstractController
 {
     /**
      * @Route("/howto", name="howto")