refactor(neon): make SettingsStorage and AppStorage internal

Signed-off-by: Nikolas Rimikis <rimikis.nikolas@gmail.com>

packages/neon/neon/lib/settings.dart

@@ -2,6 +2,5 @@ export 'package:neon/src/models/label_builder.dart';
 export 'package:neon/src/settings/models/nextcloud_app_options.dart';
 export 'package:neon/src/settings/models/options_category.dart';
 export 'package:neon/src/settings/models/select_option.dart';
-export 'package:neon/src/settings/models/storage.dart';
 export 'package:neon/src/settings/models/toggle_option.dart';
 export 'package:neon/src/settings/widgets/settings_list.dart';

packages/neon/neon/lib/src/settings/models/storage.dart

@@ -1,6 +1,7 @@
 import 'package:meta/meta.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+@internal
 abstract interface class SettingsStorage {
   String? getString(final String key);
 
@@ -14,6 +15,8 @@ abstract interface class SettingsStorage {
   Future<bool> remove(final String key);
 }
 
+@immutable
+@internal
 class AppStorage implements SettingsStorage {
   AppStorage(this._id);