feat: multi arch build using qemu
Motivation
This handy docker packaging missed images for the arm64 nodes that compose my cluster
Notes
Because of a known limitation of buildx, I was unable to --load first and docker push later without deep changes to the script. Using buildx --push is the most straightforward way to do it and the subsequent docker run based test remains.
During my test, I overrode IMAGE_NAME with zar3bski/radicale to populate this repo https://hub.docker.com/repository/docker/zar3bski/radicale/tags if you want to check.
Cheers