Remove remaining uses of wgContentTranslationDomainTemplate

Removed mw.cx.doCX, it is now part of mw.cx.SiteMapper, which can be
accessed via mw.cx.siteMapper (but dependency injection is preferred).

Change-Id: I9c0b5dca07f0d426724d034b3123f70bf83b1850
Merge "Remove remaining uses of wgContentTranslationDomainTemplate"