refactor(neon): make stuff immutable

packages/neon/neon/lib/src/utils/account_options.dart

@@ -6,6 +6,7 @@ import 'package:neon/src/settings/models/select_option.dart';
 import 'package:neon/src/settings/models/storage.dart';
 
 @internal
+@immutable
 class AccountSpecificOptions {
   AccountSpecificOptions(
     this._storage,

packages/neon/neon/lib/src/utils/app_route.dart

@@ -4,6 +4,7 @@ import 'package:go_router/go_router.dart';
 /// [RouteData] for the initial page of an app.
 ///
 /// Subclasses must override one of [build] or [redirect].
+@immutable
 abstract class NeonAppRoute extends GoRouteData {
   const NeonAppRoute();
 

packages/neon/neon/lib/src/utils/global_options.dart

@@ -16,6 +16,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 const unifiedPushNextPushID = 'org.unifiedpush.distributor.nextpush';
 
 @internal
+@immutable
 class GlobalOptions {
   GlobalOptions(
     this._sharedPreferences,

packages/neon/neon/lib/src/utils/push_utils.dart

@@ -22,6 +22,7 @@ import 'package:nextcloud/nextcloud.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 @internal
+@immutable
 class PushUtils {
   static Future<RSAKeypair> loadRSAKeypair(final AppStorage storage) async {
     const keyDevicePrivateKey = 'device-private-key';

packages/neon/neon/lib/src/utils/request_manager.dart

@@ -9,8 +9,9 @@ import 'package:rxdart/rxdart.dart';
 import 'package:sqflite/sqflite.dart';
 import 'package:xml/xml.dart' as xml;
 
+@immutable
 class RequestManager {
-  RequestManager([
+  const RequestManager([
     this.cache,
   ]);