updated project linter-rules and enforced them

lib/model/accountData.dart

@@ -10,8 +10,8 @@ import 'package:shared_preferences/shared_preferences.dart';
 import 'accountModel.dart';
 
 class AccountData {
-  static const _usernameField = "username";
-  static const _passwordField = "password";
+  static const _usernameField = 'username';
+  static const _passwordField = 'password';
   
   static final AccountData _instance = AccountData._construct();
   final Future<SharedPreferences> _storage = SharedPreferences.getInstance();
@@ -29,21 +29,21 @@ class AccountData {
   String? _password;
 
   String getUsername() {
-    if(_username == null) throw Exception("Username not initialized");
+    if(_username == null) throw Exception('Username not initialized');
     return _username!;
   }
 
   String getPassword() {
-    if(_password == null) throw Exception("Password not initialized");
+    if(_password == null) throw Exception('Password not initialized');
     return _password!;
   }
 
   String getUserSecret() {
-    return sha512.convert(utf8.encode("${AccountData().getUsername()}:${AccountData().getPassword()}")).toString();
+    return sha512.convert(utf8.encode('${AccountData().getUsername()}:${AccountData().getPassword()}')).toString();
   }
 
   Future<String> getDeviceId() async {
-    return sha512.convert(utf8.encode("${getUserSecret()}@${await FirebaseMessaging.instance.getToken()}")).toString();
+    return sha512.convert(utf8.encode('${getUserSecret()}@${await FirebaseMessaging.instance.getToken()}')).toString();
   }
 
   Future<void> setData(String username, String password) async {
@@ -84,7 +84,7 @@ class AccountData {
   }
 
   String buildHttpAuthString() {
-    if(!isPopulated()) throw Exception("AccountData (e.g. username or password) is not initialized!");
-    return "$_username:$_password";
+    if(!isPopulated()) throw Exception('AccountData (e.g. username or password) is not initialized!');
+    return '$_username:$_password';
   }
 }

lib/model/breakers/BreakerProps.dart

@@ -26,7 +26,7 @@ class BreakerProps extends DataHolder {
     for(var key in breakers.regional.keys) {
       GetBreakersReponseObject value = breakers.regional[key]!;
 
-      if(int.parse(key.split("b")[1]) >= selfVersion) {
+      if(int.parse(key.split('b')[1]) >= selfVersion) {
         if(value.areas.contains(type)) return value.message;
       }
     }

lib/model/chatList/chatProps.dart

@@ -4,7 +4,7 @@ import '../../api/marianumcloud/talk/chat/getChatResponse.dart';
 import '../dataHolder.dart';
 
 class ChatProps extends DataHolder {
-  String _queryToken = "";
+  String _queryToken = '';
   DateTime _lastTokenSet = DateTime.now();
 
   GetChatResponse? _getChatResponse;

lib/model/endpointData.dart

@@ -21,7 +21,7 @@ class Endpoint {
   String domain;
   String path;
 
-  Endpoint({required this.domain, this.path = ""});
+  Endpoint({required this.domain, this.path = ''});
 
   String full() {
     return domain + path;
@@ -40,17 +40,17 @@ class EndpointData {
   EndpointMode getEndpointMode() {
     late String existingName;
     existingName = AccountData().getUsername();
-    return existingName.startsWith("google") ? EndpointMode.stage : EndpointMode.live;
+    return existingName.startsWith('google') ? EndpointMode.stage : EndpointMode.live;
   }
 
   Endpoint webuntis() {
     return EndpointOptions(
       live: Endpoint(
-        domain: "peleus.webuntis.com",
+        domain: 'peleus.webuntis.com',
       ),
       staged: Endpoint(
-        domain: "mhsl.eu",
-        path: "/marianum/marianummobile/webuntis/public/index.php/api"
+        domain: 'mhsl.eu',
+        path: '/marianum/marianummobile/webuntis/public/index.php/api'
       ),
     ).get(getEndpointMode());
   }
@@ -58,11 +58,11 @@ class EndpointData {
   Endpoint nextcloud() {
     return EndpointOptions(
       live: Endpoint(
-        domain: "cloud.marianum-fulda.de",
+        domain: 'cloud.marianum-fulda.de',
       ),
       staged: Endpoint(
-        domain: "mhsl.eu",
-        path: "/marianum/marianummobile/cloud",
+        domain: 'mhsl.eu',
+        path: '/marianum/marianummobile/cloud',
       )
     ).get(getEndpointMode());
   }

lib/model/files/filesProps.dart

@@ -12,7 +12,7 @@ extension ExtendedList on List {
 
 class FilesProps extends DataHolder {
   List<String> folderPath = List<String>.empty(growable: true);
-  String currentFolderName = "Home";
+  String currentFolderName = 'Home';
 
   ListFilesResponse? _listFilesResponse;
   ListFilesResponse get listFilesResponse => _listFilesResponse!;
@@ -32,7 +32,7 @@ class FilesProps extends DataHolder {
     _listFilesResponse = null;
     notifyListeners();
     ListFilesCache(
-      path: folderPath.isEmpty ? "/" : folderPath.join("/"),
+      path: folderPath.isEmpty ? '/' : folderPath.join('/'),
       onUpdate: (ListFilesResponse data) => {
         _listFilesResponse = data,
         notifyListeners(),
@@ -48,7 +48,7 @@ class FilesProps extends DataHolder {
 
   void popFolder() {
     folderPath.removeLast();
-    if(folderPath.isEmpty) currentFolderName = "Home";
+    if(folderPath.isEmpty) currentFolderName = 'Home';
     run();
   }
 }

lib/model/timetable/timetableProps.dart

@@ -49,8 +49,8 @@ class TimetableProps extends DataHolder {
   @override
   void run({renew}) {
     GetTimetableCache(
-      startdate: int.parse(DateFormat("yyyyMMdd").format(startDate)),
-      enddate: int.parse(DateFormat("yyyyMMdd").format(endDate)),
+      startdate: int.parse(DateFormat('yyyyMMdd').format(startDate)),
+      enddate: int.parse(DateFormat('yyyyMMdd').format(endDate)),
       onUpdate: (GetTimetableResponse data) => {
         _getTimetableResponse = data,
         notifyListeners(),