Implement Webuntis HTTP Api and Display

lib/api/webuntis/queries/getRooms/getRoomsCache.dart

@@ -0,0 +1,23 @@
+import 'dart:convert';
+
+import 'package:marianum_mobile/api/requestCache.dart';
+import 'package:marianum_mobile/api/webuntis/queries/getRooms/getRoomsResponse.dart';
+
+import 'getRooms.dart';
+
+class GetRoomsCache extends RequestCache<GetRoomsResponse> {
+  GetRoomsCache({onUpdate}) : super(60 * 60, onUpdate) {
+    start("rooms", "data");
+  }
+
+  @override
+  Future<GetRoomsResponse> onLoad() {
+    return GetRooms().run();
+  }
+
+  @override
+  GetRoomsResponse onLocalData(String json) {
+    return GetRoomsResponse.fromJson(jsonDecode(json));
+  }
+
+}

lib/api/webuntis/queries/getRooms/getRoomsResponse.dart

@@ -3,7 +3,7 @@ import 'package:marianum_mobile/api/webuntis/apiResponse.dart';
 
 part 'getRoomsResponse.g.dart';
 
-@JsonSerializable()
+@JsonSerializable(explicitToJson: true)
 class GetRoomsResponse extends ApiResponse {
   Set<GetRoomsResponseObject> result;
 

lib/api/webuntis/queries/getRooms/getRoomsResponse.g.dart

@@ -16,7 +16,7 @@ GetRoomsResponse _$GetRoomsResponseFromJson(Map<String, dynamic> json) =>
 
 Map<String, dynamic> _$GetRoomsResponseToJson(GetRoomsResponse instance) =>
     <String, dynamic>{
-      'result': instance.result.toList(),
+      'result': instance.result.map((e) => e.toJson()).toList(),
     };
 
 GetRoomsResponseObject _$GetRoomsResponseObjectFromJson(