BRAKING refactor project structure.

Refactor: the project is now divided into a more clear structure, with **Infrastructure** and **Application** layers added.

Refactor: configurations are split into sections for different layers.

Fix: now EF Core related operations, such as migration, should be invoked in `OptixServe.Infrastructure`, with config file and data dir passed into `dotnet ef` command. See `OptixServe.Infrastructure/Utilites/DesignTimeDbContextFactory.cs` for details.

Fix: EF migrations are ignored in gitignore on purpose in early development.

OptixServe.Core/Data/AppDbContext.cs

@@ -1,21 +0,0 @@
-using Microsoft.EntityFrameworkCore;
-using OptixServe.Core.Models;
-
-namespace OptixServe.Core.Data;
-
-public class AppDbContext(DbContextOptions options) : DbContext(options)
-{
-    public DbSet<User> Users { get; set; } = null!;
-
-    protected override void OnModelCreating(ModelBuilder modelBuilder)
-    {
-        modelBuilder.Entity<User>(user =>
-        {
-            user.HasKey(u => u.Id);
-        });
-
-        modelBuilder.Entity<User>().HasData([
-            new() {Id = "1", UserName = "admin", Password = "admin12345"}
-        ]);
-    }
-}

OptixServe.Core/Data/DbInitializer.cs

@@ -1,11 +0,0 @@
-namespace OptixServe.Core.Data;
-
-public class DbInitializer(AppDbContext dbContext)
-{
-    private readonly AppDbContext _context = dbContext;
-
-    public void Initialize()
-    {
-        _context.Database.EnsureCreated();
-    }
-}

OptixServe.Core/OptixServe.Core.csproj

@@ -6,8 +6,5 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.6" />
-  </ItemGroup>
 
 </Project>

OptixServe.Core/Services/UserService.cs

@@ -1,31 +0,0 @@
-using OptixServe.Core.Data;
-using OptixServe.Core.Models;
-
-namespace OptixServe.Core.Services;
-
-public interface IUserService
-{
-    IEnumerable<User> GetUsers();
-    User? GetUserById(string id);
-    User? GetUserByUsername(string username);
-}
-
-public class UserService(AppDbContext dbContext) : IUserService
-{
-    private readonly AppDbContext _dbContext = dbContext;
-
-    public User? GetUserById(string id)
-    {
-        return _dbContext.Users.FirstOrDefault(u => u.Id == id);
-    }
-
-    public User? GetUserByUsername(string username)
-    {
-        return _dbContext.Users.FirstOrDefault(u => u.UserName == username);
-    }
-
-    public IEnumerable<User> GetUsers()
-    {
-        return _dbContext.Users.AsEnumerable();
-    }
-}