Create constant CORE_PATH and rework project loaders

bootstrap/app.php

@@ -1,9 +1,11 @@
 <?php
 
-require_once __DIR__.'/../../../vendor/autoload.php';
+define('CORE_PATH',  __DIR__.'/../../../..');
+
+require_once CORE_PATH . '/vendor/autoload.php';
 
 (new Laravel\Lumen\Bootstrap\LoadEnvironmentVariables(
-    dirname(__DIR__) . '/../../../'
+    CORE_PATH . '/'
 ))->bootstrap();
 
 date_default_timezone_set(env('APP_TIMEZONE', 'UTC'));