Add X13 WebP module for image conversion to next-generation formats

- Implemented the X13Webp class with core functionalities for converting images to WebP format.
- Added support for different PHP versions and defined constants for versioning.
- Included translation strings for various user interface elements and messages.
- Created XML file for module versioning.

modules/x13webp/vendor/composer/autoload_classmap.php

@@ -0,0 +1,10 @@
+<?php
+
+// autoload_classmap.php @generated by Composer
+
+$vendorDir = dirname(dirname(__FILE__));
+$baseDir = dirname($vendorDir);
+
+return array(
+    'X13Webp' => $baseDir . '/x13webp.php',
+);