Enable Redis async import

- using javibravo/simpleue
- internal config value are now `import_with_redis` & `import_with_rabbit` which are more clear
- if both option are enable rabbit will be choosen
- services imports related to async are now splitted into 2 files: `redis.yml` & `rabbit.yml`
-

src/Wallabag/CoreBundle/Command/InstallCommand.php

@@ -322,7 +322,12 @@ class InstallCommand extends ContainerAwareCommand
                 'section' => 'import',
             ],
             [
-                'name' => 'rabbitmq',
+                'name' => 'import_with_redis',
+                'value' => '0',
+                'section' => 'import',
+            ],
+            [
+                'name' => 'import_with_rabbitmq',
                 'value' => '0',
                 'section' => 'import',
             ],