Supporting arm64; a checklist

[vielmetti]

From the docs:

For etcd to officially support a new platform as stable, a few requirements are necessary to ensure acceptable quality:

This issue tracks those elements required for "stable" support for arm64, and identifies the checklist of support requirements; it's similar to #9409 (IBM s390x) or the work done to get ppc64le supported.

• An "official" maintainer for the platform with clear motivation; someone must be responsible for taking care of the platform.
• Set up CI for build; etcd must compile. (Done since *: add multi-arch support in release binaries #7714 , work by @glevand )
• Set up CI for running unit tests; etcd must pass simple tests.
• Set up CI (TravisCI, SemaphoreCI or Jenkins) for running integration tests; etcd must pass intensive tests.
• (Optional) Set up a functional testing cluster; an etcd cluster should survive stress testing.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[vielmetti]

Affirming that there is still interest in this, to defeat the stale bot.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.