implemented marianum message dataloader

lib/api/mhsl/message/getMessages/getMessages.dart

@@ -7,11 +7,8 @@ import 'getMessagesResponse.dart';
 
 class GetMessages extends MhslApi<GetMessagesResponse> {
   GetMessages() : super('message/messages.json');
-
-
   @override
   GetMessagesResponse assemble(String raw) => GetMessagesResponse.fromJson(jsonDecode(raw));
-
   @override
   Future<http.Response> request(Uri uri) => http.get(uri);
 }