Ported WikiaLabs changes from dev branch

Merge pull request #4210 from Wikia/CE-934
(CE-934) Add Maps to WikiFeatures
MOB-2250: Pass user language with loader request
Added language caching for local storage as well
Put `mw` in the right context
Merge pull request #4237 from Wikia/MOB-2250

MOB-2250: Pass user language with loader request
Merge pull request #4236 from Wikia/maps-p2-fixes-and-wiki-labs

Ported WikiaLabs changes from dev branch and added P2s fixes