This will be used when running infrastructure code locally
(e.g. recipes) to correctly interact with LUCI service APIs
(such as luci-scheduler.appspot.com).

It is also generically useful to explore and interact with LUCI
service APIs on the command line (for debugging/scripting).

R=tandrii@chromium.org, vadimsh@chromium.org

Bug: 808677
Change-Id: I41cfd4cc7e2d245d3a5d2be83f9879f92a8d1bca
Reviewed-on: https://chromium-review.googlesource.com/905457
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>