Dashboard - Create histograms per bot for alert statistics
Dashboard - Create histograms per bot for alert statistics

Bug: chromium:890025
Change-Id: I590f796c1c46c2cf1213186fb223d5efb09d5b4a
Reviewed-on: https://chromium-review.googlesource.com/1251702
Reviewed-by: Ben Hayden <d3ffe0e065c2328e497bb32a07f4dcb29138ef5b@chromium.org>
Commit-Queue: Simon Hatch <490a224d89645d3fea983d7189ce51bde0a00c1d@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult