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

api/tests/_pages/SignupRoute.php

@@ -0,0 +1,20 @@
+<?php
+namespace api\tests\_pages;
+
+class SignupRoute extends BasePage {
+
+    public function register(array $registrationData) {
+        $this->getActor()->sendPOST('/api/signup', $registrationData);
+    }
+
+    public function sendRepeatMessage($email = '') {
+        $this->getActor()->sendPOST('/api/signup/repeat-message', ['email' => $email]);
+    }
+
+    public function confirm($key = '') {
+        $this->getActor()->sendPOST('/api/signup/confirm', [
+            'key' => $key,
+        ]);
+    }
+
+}