Add LiipThemeBundle

Re-defined the config / user relation to be OneToOne bidirectionnal.
ConfigType is now a service so I can inject the list of available themes that are also used by LiipThemeBundle

Force sqlite for test
In case of people use a different driver in parameter.yml (yes I do :))

app/config/config_test.yml

@@ -17,4 +17,6 @@ swiftmailer:
 
 doctrine:
     dbal:
-        path: %kernel.root_dir%/../data/db/poche_test.sqlite
+        driver: pdo_sqlite
+        path: %kernel.root_dir%/../data/db/wallabag_test.sqlite
+        host: localhost