Move to controller as a service

Mostly using autowiring to inject deps.
The only tricky part was for import because all producer use the same class and have a different alias. So we must write them down in the service definition, autowiring doesn't work in that case.

Usually:
- if a controller has a constructor, it means injected services are at least re-used once in actions
- otherwise, service are injected per action

src/Wallabag/ApiBundle/Controller/ConfigRestController.php

@@ -27,11 +27,11 @@ class ConfigRestController extends WallabagRestController
      *
      * @return JsonResponse
      */
-    public function getConfigAction()
+    public function getConfigAction(SerializerInterface $serializer)
     {
         $this->validateAuthentication();
 
-        $json = $this->get(SerializerInterface::class)->serialize(
+        $json = $serializer->serialize(
             $this->getUser()->getConfig(),
             'json',
             SerializationContext::create()->setGroups(['config_api'])