Add support for Apache Mobile Filter

Apache Mobile Filter is an apache module that provides mobile
detection. Adding support for this adds an easy avenue for
MediaWiki users to enable MobileFrontend without the need for
setting X-Device through a caching layer.

Change-Id: Ic01a1ccb1389068a4c0e6da4bcee4519ac1dd85f
Merge "Add support for Apache Mobile Filter"