Migrate CI to GitHub Actions

[taiki-e]

This tracks the migration of CI to GitHub Actions from Azure Pipelines.

The following jobs need to be migrated.
Checked jobs have been migrated to GitHub Actions.

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• test_tokio; done in Start migrating CI to Github Actions #2531
• test_sub_crates; done in Start migrating CI to Github Actions #2531
• test_integration; done in Start migrating CI to Github Actions #2531
• test_build
• miri
• cross
• check_features
• minrust
• rustfmt
• clippy
• docs
• tsan
• loom
• deploy-docs

Also, we need to look out what ci/azure-is-release.yml is actually doing and decide whether to add to GitHub Actions. #2531 (comment)

I also haven't yet included the functionality from azure-is-release.yml because I haven't looked into how it interacts with the rest of the pipeline and I don't think it affects anything in what I've implemented so far.

[taiki-e]

I'm not sure if I have the bandwidth to do this now, but assign to self as a reviewer.

[taiki-e]

done in #2680