Add PayPal webhook handler and marketing styles

- Implemented PayPal webhook for handling payment notifications, including signature verification and transaction updates.
- Created invoice generation and license management for software upgrades upon successful payment.
- Added comprehensive logging for debugging purposes.
- Introduced new CSS styles for the marketing file management system, including layout, toolbar, breadcrumb navigation, search filters, and file management UI components.

api/v2/get/service.php

@@ -0,0 +1,41 @@
+<?php
+defined($security_key) or exit;
+
+//------------------------------------------
+// Application related calls
+//------------------------------------------
+$request = explode('/', trim($_SERVER['PATH_INFO'],'/'));
+$action = $request[2] ?? '';
+
+
+if ($action == 'init'){
+    include './settings/systemservicetool_init.php';  
+    echo json_encode($init);		
+}
+elseif ($action == 'questions' && (isset($_GET['type']) && $_GET['type'] != '')){
+ 
+    include './settings/systemservicetool.php';
+
+    //build questions
+    switch ($_GET['type']) {
+        case 'visual':
+        $arrayQuestions = $arrayQuestions_visual;
+            break;
+
+        case 'final':
+        $arrayQuestions = $arrayQuestions_finalize;
+            break;
+
+        case 'cartest':
+            include './settings/systemcartest.php';
+            $arrayQuestions = $arrayQuestions_cartest;
+                break;
+        }
+    //Return JSON
+    echo json_encode($arrayQuestions);
+}
+else {
+    http_response_code(400);
+}
+
+?>