Automate generation of DockerFiles and DockerHub deployment

[karianna]

@karianna I'm a little bit unsure on what the requirement here is (Replacing dockerhub pushes with an AdoptOpenJDK location?) I wouldn't have thought we'd replace Dockerhub so is this about desyncing the need to ship the two ARM platforms at the same time as the others (which seems like a reasonable requirement)

Originally posted by @sxa in https://github.com/AdoptOpenJDK/openjdk-docker/issues/303#issuecomment-804206724