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

common/tests/fixtures/data/webhooks.php

@@ -0,0 +1,21 @@
+<?php
+return [
+    'webhook-with-secret' => [
+        'id' => 1,
+        'url' => 'http://localhost:80/webhooks/ely',
+        'secret' => 'my-secret',
+        'created_at' => 1531054333,
+    ],
+    'webhook-without-secret' => [
+        'id' => 2,
+        'url' => 'http://localhost:81/webhooks/ely',
+        'secret' => null,
+        'created_at' => 1531054837,
+    ],
+    'webhook-without-events' => [
+        'id' => 3,
+        'url' => 'http://localhost:82/webhooks/ely',
+        'secret' => null,
+        'created_at' => 1531054990,
+    ],
+];