Consistency tweaks in preparation for adding extension to translatewiki.net

* Add special page alias file
* Move language sections: 1st: en, 2nd: qqq, translations
* Rephrase description message to add a label to the special page link
* Remove redundant 'description' key from $wgExtensionCredits

Change-Id: Ib81563bca0b746fb50ac066465ff646f1a7c6220