TF-297 Store language selected when user changed

lib/features/manage_account/data/local/language_cache_manager.dart

@@ -0,0 +1,20 @@
+
+import 'dart:ui';
+
+import 'package:shared_preferences/shared_preferences.dart';
+
+class LanguageCacheManager {
+  static const keyLanguageCode = 'LANGUAGE_CODE';
+  static const keyCountryCode = 'COUNTRY_CODE';
+
+  final SharedPreferences _sharedPreferences;
+
+  LanguageCacheManager(this._sharedPreferences);
+
+  Future<void> persistLanguage(Locale localeCurrent) async {
+    await Future.wait([
+      _sharedPreferences.setString(keyLanguageCode, localeCurrent.languageCode),
+      _sharedPreferences.setString(keyCountryCode, localeCurrent.countryCode ?? '')
+    ]);
+  }
+}