Adding User Controller and Delete endpoint

Services/UserService.cs

@@ -23,6 +23,12 @@ public class UserService
     public async Task<List<User>> GetAllAsync() =>
         await _users.Find(_ => true).ToListAsync();
 
+    public async Task<bool> DeleteAsync(string username)
+    {
+        var result = await _users.DeleteOneAsync(u => u.Username == username);
+        return result.DeletedCount > 0;
+    }
+
     public async Task CreateAsync(User user) =>
         await _users.InsertOneAsync(user);