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/Entities/FactorDetails.cs

@@ -4,7 +4,7 @@ public class FactorDetails : BaseAuditableEntity
 {
     public long ProductId { get; set; }
     //Product Navigation Property
-    public virtual Products Product { get; set; }
+    public virtual Product Product { get; set; }
     public int Count { get; set; }
     public long UnitPrice { get; set; }
     public int UnitDiscount { get; set; }