Process main page (linklist) through Slim controller

Including a bunch of improvements on the container,
and helper used across new controllers.

application/api/ApiMiddleware.php

@@ -71,7 +71,14 @@ class ApiMiddleware
             $response = $e->getApiResponse();
         }
 
-        return $response;
+        return $response
+            ->withHeader('Access-Control-Allow-Origin', '*')
+            ->withHeader(
+                'Access-Control-Allow-Headers',
+                'X-Requested-With, Content-Type, Accept, Origin, Authorization'
+            )
+            ->withHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS')
+        ;
     }
 
     /**