extracted interfaces for services, to aid in creating tests

src/Service/LoginInterface.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Service;
+
+use App\Data\Payload;
+use Psr\Cache\InvalidArgumentException;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+interface LoginInterface {
+    /** @throws InvalidArgumentException */
+    public function checkToken(Payload $payload, Request $request): ?Response;
+}