Implement Webuntis HTTP Api and Display

lib/api/webuntis/queries/getSubjects/getSubjectsCache.dart

@@ -0,0 +1,23 @@
+import 'dart:convert';
+
+import 'package:marianum_mobile/api/requestCache.dart';
+import 'package:marianum_mobile/api/webuntis/queries/getSubjects/getSubjectsResponse.dart';
+
+import 'getSubjects.dart';
+
+class GetSubjectsCache extends RequestCache<GetSubjectsResponse> {
+  GetSubjectsCache({onUpdate}) : super(60 * 60, onUpdate) {
+    start("subjects", "data");
+  }
+
+  @override
+  Future<GetSubjectsResponse> onLoad() {
+    return GetSubjects().run();
+  }
+
+  @override
+  onLocalData(String json) {
+    return GetSubjectsResponse.fromJson(jsonDecode(json));
+  }
+
+}