DefaultSettings: use Mediawiki:Wikia.css / js in Venus
Venus: add .mediawiki CSS class to <body>
AssetsManager: always allow ResourceLoader assets to be loaded (even in strict mode)
CON-NewArticle: Fix for js integration tests
Merge pull request #5365 from Wikia/CON-2113-load-wikia.css-in-venus

CON-2113: load Wikia.css in Venus