creating UserControllerInterface.php

server/web_app/src/Interface/UserControllerInterface.php

+<?php
+namespace App\Interface;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+interface UserControllerInterface
+{
+    public function createUser(Request $req): Response;
+
+    public function getAllUsers(): Response;
+
+    public function getUserById(int $user_id): Response;
+
+    public function updateUser(int $user_id, Request $req): Response;
+
+    public function deleteUser(int $user_id): Response;
+
+    public function authenticateUser(string $username, string $password): Response;
+
+    public function changePassword(int $user_id, string $old_password, string $new_password): Response;
+}