Stats: track how frequently contact images are present incall

For retail devices (and installer builds), introduce tags to be read
by a separate, additional, package.

This will not be read or collected in any community (nightly/M/etc) or
self-built build.

Change-Id: I7f52f18a53ade50e0274af633cb7c26566332ee7
(cherry picked from commit 36e6ee373e4cbe86cf349edb1b897f23ea8bc3f1)
Merge remote-tracking branch 'upstream/stable/cm-11.0' into stable/cm-11.0