Add Identity configuration, DTOs and Mappers

-Configured Identity using a custom User model to manage authentication and authorization, to be used in the project.
- Added multiple DTOs (Data Transfer Objects).
- Added multiple Mappers ( manual mapping).
- Updated AppDbContext and User model to fully integrate with Identity framework for user management.
-Added relationships between models.
Note : no migration yet

survey-beta/Program.cs

@@ -1,21 +1,30 @@
+using Microsoft.AspNetCore.Identity;
 using Microsoft.EntityFrameworkCore;
 using survey_beta.DataBaseContext;
+using survey_beta.Models;
+using survey_beta.Services;
 
 var builder = WebApplication.CreateBuilder(args);
 
 // Add services to the container
 builder.Services.AddDbContext<AppDbContext>(options =>
     options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection")));
-
 builder.Services.AddControllers(); 
 builder.Services.AddEndpointsApiExplorer(); 
 
 var app = builder.Build();
 
 // Configure the HTTP request pipeline.
+builder.Services.AddIdentity<User, IdentityRole>()
+            .AddEntityFrameworkStores<AppDbContext>()
+            .AddDefaultTokenProviders();
+
+builder.Services.AddScoped<UserService>();
 
 app.UseHttpsRedirection();
 
+app.UseAuthentication();
+
 app.UseAuthorization();
 
 app.MapControllers();