life quality changes

- refactored SurveyController.cs
- added ProducesResponseType to every endpoint in every controller
- remade mappers

SurveyBackend/SurveyBackend.API/Mappers/UserDTOs/UserRegistrationMapper.cs

@@ -1,16 +0,0 @@
-using SurveyBackend.Core.Models;
-using SurveyBackend.Core.Services;
-using SurveyBackend.DTOs;
-
-namespace SurveyBackend.Mappers.UserDTOs;
-
-public static class UserRegistrationMapper
-{
-    public static User UserRegistrationToModel(UserRegistrationDto dto) => new User
-    {
-        Email = dto.Email,
-        FirstName = dto.FirstName,
-        LastName = dto.LastName,
-        Password = dto.Password,
-    };
-}