[CORE][COMPOSER] Move extlib packages with immediate composer correspondent to composer dependencies

This adds a composer.json for all dependencies that are available

vendor/ezyang/htmlpurifier/library/HTMLPurifier/Language/messages/en-x-test.php

@@ -0,0 +1,11 @@
+<?php
+
+// private language message file for unit testing purposes
+
+$fallback = 'en';
+
+$messages = array(
+    'HTMLPurifier' => 'HTML Purifier X'
+);
+
+// vim: et sw=4 sts=4