Add custom doctrine subscriber for SQLite

Since SQLite doesn’t handle cascade remove by default, we need to handle it manually.

Also some refacto

src/Wallabag/CoreBundle/Resources/config/services.yml

@@ -88,6 +88,17 @@ services:
         arguments:
             - WallabagCoreBundle:Tag
 
+    wallabag_core.listener.registration_confirmed:
+        class: Wallabag\CoreBundle\EventListener\RegistrationConfirmedListener
+        arguments:
+            - "@doctrine.orm.entity_manager"
+            - "%wallabag_core.theme%"
+            - "%wallabag_core.items_on_page%"
+            - "%wallabag_core.rss_limit%"
+            - "%wallabag_core.language%"
+        tags:
+            - { name: kernel.event_subscriber }
+
     wallabag_core.helper.entries_export:
         class: Wallabag\CoreBundle\Helper\EntriesExport
         arguments:
@@ -129,3 +140,10 @@ services:
         arguments:
             - '@twig'
             - '%kernel.debug%'
+
+    wallabag_core.subscriber.sqlite_cascade_delete:
+        class:  Wallabag\CoreBundle\Subscriber\SQLiteCascadeDeleteSubscriber
+        arguments:
+            - "@doctrine"
+        tags:
+            - { name: doctrine.event_subscriber }