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/views/templates/variables.tpl

@@ -0,0 +1,21 @@
+<script>
+{foreach from=$x13webp_js_variables item=value key=k}
+    {if !empty($k) && is_string($k)}
+        {if is_bool($value)}
+            var {$k} = {$value|var_export:true};
+        {elseif is_int($value)}
+            var {$k} = {$value|intval};
+        {elseif is_float($value)}
+            var {$k} = {$value|floatval|replace:',':'.'};
+        {elseif is_string($value)}
+            var {$k} = '{$value|strval}';
+        {elseif is_array($value) || is_object($value)}
+            var {$k} = {$value|json_encode};
+        {elseif is_null($value)}
+            var {$k} = null;
+        {else}
+            var {$k} = '{$value|@addcslashes:'\''}';
+        {/if}
+    {/if}
+{/foreach}
+</script>