Namespace mediawiki repos for deployment

The early naming scheme for mediawiki repos didn't take into
account that other repos would exist and didn't namespace it. This
commit moves all mediawiki repos into the mediawiki directory
namespace.

Change-Id: I068ad2477a92e8a7eb2eff05f0d8f96cdf60e562
Merge "Namespace mediawiki repos for deployment" into production