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.php

@@ -154,7 +154,8 @@ if($is_jwt_valid && str_contains($version, 'v')) {
             // First check if endPoint is fileUpload
             //------------------------------------------ 
             $fileUploadEndpoints = [
-                'media_upload'
+                'media_upload',
+                'marketing_upload'
             ];
 
             $isFileUploadEndpoint = in_array($collection, $fileUploadEndpoints);