* Let relbot update A-C on trunk
We already use relbot for this on fenix release branches and on all
branches for focus-android, so might as well avoid the duplication.
* Update mergify rules to auto-merge AC bumps from relbot on the main branch
* Add visual-metrics docker type.
* Add required browsertime toolchain fetches.
* Add browsertime tests for technical and visual metrics.
* Run browsertime tests in a cron task.
* Run visual metrics on all browsertime tests.
* Use spaces instead of tabs, and resolve visual-metric nits.
* Enable browsertime on pull request for testing.
* Restrict PR tests to amazon on browsertime.
* First attempt using multi_dep.
* Add a primary dependency to browsertime.
* Try by not popping.
* Debug prints.
* Make one grouping per browsertime task.
* Try without the multi_dep transform.
* Delete dependent-tasks in visual-metrics transformer.
* Update setuptools installed and copy run-on-tasks-for.
* Use get when getting run-on-tasks-for.
* Add new pinned requirements.
* Try it.
* Set run-on-tasks-for properly.
* Remove print statement.
* Remove single_dep loader, and print statements.
* Remove run-on-tasks-for testing setting.
* Restart testing, and set user to root in visual-metrics Docker.
* Remove testing settings.
* Remove fetch-content from Docker.
* Change attributes grouping method.
* Run all tests as a check.
* Undo testing changes, and fix a bad test name.
