feat:创建挂单数据库，和迁移文件

lib/common/services/database/dao/order_hold_bill_dao.dart

@@ -0,0 +1,15 @@
+import 'package:floor/floor.dart';
+
+import 'package:pj_supermarket_cloud/common/index.dart';
+
+@dao
+abstract class OrderHoldBillDao {
+  @insert
+  Future<int?> save(OrderHoldBillEntity entity);
+
+  @update
+  Future<void> edit(OrderHoldBillEntity entity);
+
+  @delete
+  Future<void> del(OrderHoldBillEntity entity);
+}