bench-bot: compare against https://github.com/paritytech/bench-bot

[joao-paulo-parity]

command-bot queues bench-bot commands to GitLab's Shell Executors, the same approach used for calculating weights before releases (https://github.com/paritytech/polkadot/blob/eb21d7c8c25547826240d10a060291599aab18e5/.gitlab-ci.yml#L522), which means that commands are executed directly in the host's shell, therefore performance should remain "bare metal". For a demo see paritytech/substrate#11566 (comment).

The new syntax is explained in #63.

The new implementation of bench-bot is decoupled from command-bot and lives in https://github.com/paritytech/pipeline-scripts/blob/master/bench-bot.sh; any updates made to that script will be effective immediately for future commands, without having to redeploy command-bot.

Other notable differences are:

• The bot stays responsive at all times during commands (fixes Fix unresponsiveness during benchmark execution bench-bot#68), meaning more commands can be queued while one is being executed

• The command queue for the current repository (to be improved by #82) can be followed from the GitLab UI, as showcased in DUMMY [do not merge][CI] Provision bm3 into a gitlab runners fleet substrate#11566 (comment)

  https://gitlab.parity.io/parity/mirrors/substrate/-/pipelines?page=1&scope=all&username=group_605_bot to know what else is being executed currently.

• It's possible to cancel a command by manually cancelling jobs through the GitLab UI or using bot commands, as showcased in DUMMY [do not merge][CI] Provision bm3 into a gitlab runners fleet substrate#11566 (comment)

  Comment /cmd cancel 2-d7e99edd-ab60-4250-866a-9eec0c1b5213 to cancel this command or /cmd cancel to cancel all commands in this pull request.

• Weights can be downloaded by artifacts if the push fails (fixes Upload the weight's diff if it fails to push for some reason bench-bot#54), as showcased in DUMMY [do not merge][CI] Provision bm3 into a gitlab runners fleet substrate#11566 (comment)

  If any artifacts were generated, you can download them from https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/1654903/artifacts/download

• Implemented Support multiple commands per comment bench-bot#81

• Fixed Can't find source repository if the fork has a different name than the repo bench-bot#86

• Fixed Support PRs which are not against Master Branch bench-bot#75

Some planned tickets from https://github.com/paritytech/bench-bot/issues were copied or moved to this repository: https://github.com/paritytech/pipeline-scripts/issues?q=is%3Aissue+is%3Aopen+bench-bot+created%3A%3C%3D2022-06-30. If you find that some important ticket was not brought over or not implemented already, feel free to create a new ticket.