Add statistics feature with bookings tracking functionality

Introduce a scalable statistics architecture including `statistics` class, interface, and related implementations. Added support for tracking new bookings with routes and data handling through `bookings_s` and `statistic_t`. Integrated the feature into the application using autoloaders and response mechanisms.

services/nginx/app/index.php

@@ -28,6 +28,13 @@ foreach ( glob(WD . '/traits/*.php') as $trait ) {
     require_once $trait;
 }
 
+/**
+ * Load all statistics
+ */
+foreach ( glob(WD . '/statistics/*.php') as $statistic ) {
+    require_once $statistic;
+}
+
 /** Load all Classes */
 require_once 'classes/encrypt.php';
 require_once 'classes/authentication.php';
@@ -43,6 +50,7 @@ require_once 'classes/slack.php';
 require_once 'classes/wordpress_bookings_remote.php';
 require_once 'classes/language_packs.php';
 require_once 'classes/economic.php';
+require_once 'classes/statistics.php';
 
 /**
  * Modules