Updated mediawiki/extensions
Project: mediawiki/extensions/GettingStarted  7a4a012640b2536ce45a8c2cd81f06e08a17f3d6

Convert CSS to LESS

* Rename all .css files to .less
* Start using some LESS language features to tidy up
  ext.gettingstarted.return.less and
  ext.gettingstarted.taskToolbar.less
* Remove the unused ext.gettingstarted.css file

Change-Id: I09e81df3a945213727a5c212bf001d728e7a3141