New package structure for the version 2 of the public api.

Start building up the validators required for post notificaiton.
The app/v2/errors.py is a rough sketch, will be passed a code, the error can look up the message and link for the error message.

app/v2/notifications/get_notifications.py

@@ -0,0 +1,14 @@
+from app.v2.notifications import notification_blueprint
+
+
+@notification_blueprint.route("/<uuid:id>", methods=['GET'])
+def get_notification_by_id(id):
+    pass
+
+
+@notification_blueprint.route("/", methods=['GET'])
+def get_notifications():
+    # validate notifications request arguments
+    # fetch all notifications
+    # return notifications_response schema
+    pass