Flatten MedaWiki deploy into a single git repo
Maniphest Tasks: T147478
After the local compilation of wikiversions on the deployment master,
add the entirey of /srv/mediawiki to a unified git repository.
This doesn't yet attempt to change the transport mechanism for sync, nor
does it use much of the scap3 code, but it gets us to a single version
number for deployment.
This also overwrites the mediawiki-config repo as all php-* would be
Reviewers: bd808, dduvall, demon, mmodell, Release-Engineering-Team
Reviewed By: mmodell, Release-Engineering-Team
Differential Revision: https://phabricator.wikimedia.org/D429