Added option to share the app via qr-code

lib/notification/notificationTasks.dart

@@ -1,9 +1,9 @@
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter_app_badger/flutter_app_badger.dart';
-import 'package:marianum_mobile/app.dart';
 import 'package:provider/provider.dart';
 
+import '../app.dart';
 import '../model/chatList/chatListProps.dart';
 import '../model/chatList/chatProps.dart';