Add CMake bot

It uses a docker container to handle the installation of CMake.

Depends on https://skia-review.googlesource.com/c/skia/+/188305/

Bug: skia:8732
Change-Id: Ib84a46b4f0ca7f88fca4e6123c1517a84f3444b2
Reviewed-on: https://skia-review.googlesource.com/c/188036
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
18 files changed