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/Events/RefundTransactionEvent.cs

@@ -2,12 +2,12 @@ namespace CMSMicroservice.Domain.Events;
 
 public class RefundTransactionEvent : BaseEvent
 {
-    public RefundTransactionEvent(Transactions refundTransaction, Transactions originalTransaction)
+    public RefundTransactionEvent(Transaction refundTransaction, Transaction originalTransaction)
     {
         RefundTransaction = refundTransaction;
         OriginalTransaction = originalTransaction;
     }
 
-    public Transactions RefundTransaction { get; }
-    public Transactions OriginalTransaction { get; }
+    public Transaction RefundTransaction { get; }
+    public Transaction OriginalTransaction { get; }
 }