Relevant changes:

6a6825419 [bb] Add explicit experiment support to `bb ls`.
bccb58660 [bb] Make `bb get` print experiments.
0d2672023 [buildbucket/bb] Add the ability to set/block experiments in `bb add`.
2fa412040 remove is_luci property

R=gavinmak@google.com, vadimsh, yiwzhang

Bug: 1093970,1134774
Change-Id: I2860857cb86626ad235dbb87eccf19ed38800557
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2809195
Auto-Submit: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>
Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>