Updated mediawiki/skins
Project: mediawiki/skins/Vector  7f4d7f8bb621604a3226d3c9fa429a00228fa549

Add .gitignore

Used a copy of .gitignore of mediawiki/core and removed some lines,
because in this extension not all the folders which are in core.

Change-Id: I37e2bb03143b3b8f388bcf44bdcd82ce2a2ac767