Release arm64 docker images

Summary

Build and upload an arm64 version of the docker images

Proposal

Having a docker image for arm64 greately expands where gitlab can run, as even if we don't have an arm64 build for your OS, as long as your OS can run docker on arm, you will be able to run gitlab there.

Docker registries can have multiple architectures for the same tag: https://github.com/docker-library/official-images#multiple-architectures

• We should test and see if we can specify the architecture through the docker ruby api gem we are using for docker builds
• If yes, we still need to be building images for a newer OS than we are currently: #4286 (closed)
• And we need to ensure we have arm64 images for the newer OS
• Then we need to add a docker build that uses that image, and adds the arm64 architecture image to our docker release.

References

Blocked by #4286 (closed)