feat(app): Добавить fluttergen (#3)

Co-authored-by: PetrovY <y.petrov@friflex.com>

lib/l10n/gen/app_localizations_en.dart

@@ -0,0 +1,11 @@
+import 'app_localizations.dart';
+
+// ignore_for_file: type=lint
+
+/// The translations for English (`en`).
+class AppLocalizationsEn extends AppLocalizations {
+  AppLocalizationsEn([String locale = 'en']) : super(locale);
+
+  @override
+  String get helloWorld => 'Hello World!';
+}