This includes gerrit_cq_ability verifier.

TBR=sergiyb@chromium.org,rmistry@chromium.org
BUG=

Change-Id: Ifdb09bb33dd6a6fc7fdcb592e6bc4a2f8ac474ad
Reviewed-on: https://chromium-review.googlesource.com/444767Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>