Deliver notification info

Created by: stefanoborini

Notification system to communicate to the UI and other entities interested in notification.

force_bdss/tests/fixtures/test_null.json

@@ -31,6 +31,11 @@
       }
     ],
     "notification_listeners": [
+      {
+        "id": "force.bdss.enthought.factory.null_nl",
+        "model_data": {
+        }
+      }
     ]
   }
 }