Refactor namespaces and update DTO structures

Updated namespaces for DTOs and services to improve project organization. Marked several interfaces as obsolete in favor of MediatR for better request handling. Simplified `BaseUpdateDto` and other DTOs by removing `IUnique<int>` implementation. Changed return types of `CreateAsync` methods to return corresponding read DTOs. Removed reference to `DigitalData.Core.DTO` in the project file, reflecting a shift in architecture for maintainability.

DigitalData.UserManager.Application/DTOs/Module/ModuleDto.cs

@@ -1,10 +1,8 @@
-using DigitalData.Core.Abstractions;
-
-namespace DigitalData.UserManager.Application.DTOs.Module
+namespace DigitalData.UserManager.Application.DTOs.Module
 {
     public record ModuleDto(
         int Id,
         string? Name,
         string? ShortName
-    ) : IUnique<int>;
+    );
 }