Add support for arm64 docker builds

[peterbogdan]

Add support for arm64 docker builds

• Split building images into 2 steps: one to build all images for all platforms and export the digests upstream; create the new image using all digests with docker buildx imagetools create as recommended in multi-platform.md
• updated .github/actions/tagged_release/docker/codesign/action.yml to sign all images and digests pushed to docker hub
• Push latest tag on new tagged_releases
• use docker/metadata-action to tag the images
• fixed bug in .github/actions/tagged_release/github/action.yml where inputs.commit_sha was missing from file name
• fixed bug in .github/actions/build/dpkg/action.yml where the artifact could not be found and uploaded

Tagged release workflow tested here Normal release workflow tested here

Tested uploading the new images in my docker hub:

• osctrl-tls
• osctrl-cli
• osctrl-admin
• osctrl-api

[javuto]

Thank you for the pull request! I think at some point I will migrate this process to using gorelease, to make it simpler. Nice job! 👏