Deprecate repositories and update service interfaces

- Marked `IEnvelopeReceiverRepository` and several repository classes as obsolete, recommending the use of `IRepository`.
- Corrected `using` directive in `IReceiverService.cs`.
- Removed `UpdateAsync` method from `IReceiverService`.
- Enhanced `ISmsSender` interface with new properties and methods.
- Updated `ReceiverCreateDto`, `ReceiverReadDto`, and `UserReceiverDto` to enforce non-nullable properties.
- Refactored `TestReceiverController` to suggest using `MediatR`.

EnvelopeGenerator.Infrastructure/Repositories/DocumentStatusRepository.cs

@@ -1,10 +1,10 @@
 using DigitalData.Core.Infrastructure;
-using DigitalData.UserManager.Infrastructure.Repositories;
 using EnvelopeGenerator.Domain.Entities;
 using EnvelopeGenerator.Application.Contracts.Repositories;
 
 namespace EnvelopeGenerator.Infrastructure.Repositories;
 
+[Obsolete("Use IRepository")]
 public class DocumentStatusRepository : CRUDRepository<DocumentStatus, int, EGDbContext>, IDocumentStatusRepository
 {
     public DocumentStatusRepository(EGDbContext dbContext) : base(dbContext, dbContext.DocumentStatus)