RG-3443 Экран настроек локализации

lib/db.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:io';
+import 'dart:ui';
 
 import 'package:path/path.dart';
 import 'package:sqflite/sqflite.dart';
@@ -110,15 +111,18 @@ class SqliteHelper {
     return locale;
   }
 
+  Future saveLocale(String locale) async {
+    db.update(tableSettings, {columnLocale: locale});
+  }
+
   Future<int> getCurrency() async {
     Map settings = await selectAll(tableSettings);
     int currency = settings != null ? settings[columnCurrency] : null;
     return currency;
   }
 
-  Future<int> saveCurrency(int currency) async {
+  Future saveCurrency(int currency) async {
     db.update(tableSettings, {columnCurrency: currency});
-    return currency;
   }
 
   Future<Map> selectAll(String table) async {