Add validators and services for Product Galleries and Product Tags

- Implemented Create, Delete, Get, and Update validators for Product Galleries.
- Added Create, Delete, Get, and Update validators for Product Tags.
- Created service classes for handling Discount Categories, Discount Orders, Discount Products, Discount Shopping Cart, Product Categories, Product Galleries, and Product Tags.
- Each service class integrates with CQRS for command and query handling.
- Established mapping profiles for Product Galleries.

src/CMSMicroservice.Domain/Enums/ConfigurationScope.cs

@@ -23,5 +23,10 @@ public enum ConfigurationScope
     /// <summary>
     /// تنظیمات کمیسیون
     /// </summary>
-    Commission = 3
+    Commission = 3,
+    
+    /// <summary>
+    /// تنظیمات مالیات بر ارزش افزوده
+    /// </summary>
+    VAT = 4
 }