Refactor codebase resolving warnings and remove self-package imports

lib/api/webuntis/queries/getTimetable/getTimetable.dart

@@ -1,7 +1,6 @@
 import 'dart:convert';
 
-import 'package:marianum_mobile/api/webuntis/webuntisApi.dart';
-
+import '../../webuntisApi.dart';
 import 'getTimetableParams.dart';
 import 'getTimetableResponse.dart';
 

lib/api/webuntis/queries/getTimetable/getTimetableCache.dart

@@ -1,7 +1,6 @@
 import 'dart:convert';
 
-import 'package:marianum_mobile/api/requestCache.dart';
-
+import '../../../requestCache.dart';
 import '../authenticate/authenticate.dart';
 import 'getTimetable.dart';
 import 'getTimetableParams.dart';

lib/api/webuntis/queries/getTimetable/getTimetableParams.dart

@@ -1,5 +1,6 @@
 import 'package:json_annotation/json_annotation.dart';
-import 'package:marianum_mobile/api/apiParams.dart';
+
+import '../../../apiParams.dart';
 
 part 'getTimetableParams.g.dart';
 

lib/api/webuntis/queries/getTimetable/getTimetableResponse.dart

@@ -1,5 +1,6 @@
 import 'package:json_annotation/json_annotation.dart';
-import 'package:marianum_mobile/api/apiResponse.dart';
+
+import '../../../apiResponse.dart';
 
 part 'getTimetableResponse.g.dart';