Bug 1613483 - Add all Browsertime tests with visual metrics to Fenix repo. (#9087)
* 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.