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/Services/ModuleService.cs

@@ -7,6 +7,7 @@ using DigitalData.UserManager.Application.Contracts.Repositories;
 
 namespace DigitalData.UserManager.Application.Services
 {
+    [Obsolete("Use MediatR")]
     public class ModuleService : BasicCRUDService<IModuleRepository, ModuleDto, Module, int>, IModuleService
     {
         public ModuleService(IModuleRepository repository, IMapper mapper) : base(repository, mapper)