Change-Id: I8deb0f97830124829f89546dc1e945439b3e9d52
This is the final step of the process described at <https://www.mediawiki.org/wiki/Separating_skins_from_core_MediaWiki>. Corresponding core change: Idfc38503. Change-Id: I83b1efb4a489254c76e0cbda72ff34efa3d41261