Rework tests structure. Upgrade codeception to 2.5.3. Merge params configuration into app configuration.

api/tests/functional/LogoutCest.php

@@ -0,0 +1,19 @@
+<?php
+namespace api\tests\functional;
+
+use api\tests\_pages\AuthenticationRoute;
+use api\tests\FunctionalTester;
+
+class LogoutCest {
+
+    public function testLoginEmailOrUsername(FunctionalTester $I) {
+        $route = new AuthenticationRoute($I);
+
+        $I->amAuthenticated();
+        $route->logout();
+        $I->canSeeResponseContainsJson([
+            'success' => true,
+        ]);
+    }
+
+}