Align Name/Version scheme with Community Standards

Normally when you have a package that has multiple distros, versions and/or build platforms you continue to have the same top level repository and just modify the version. This allows for easier switching of the images strictly on a version basis as well as a single repository to see all of the tags. See [Python](https://hub.docker.com/_/python)

For this repo you'd be looking at something like:
asbjornenge/tezos:alphanet-{alpine,ubuntu}
asbjornenge/tezos:zeronet-{alpine,ubuntu}
asbjornenge/tezos:mainnet-{alpine,ubuntu}

Your arm based images can also push to the same repository as dockerhub breaks them up automatically for you using Digests. Which ensures that a user is being more specific with what version they are running.

Review the repository's declarative Dockerfiles and current Docker Hub image naming and publishing setup. Confirm how the existing distro, network, version, build-platform, and ARM tags are produced; done means the images use one repository with the proposed version-and-platform scheme and Docker Hub can select ARM variants by digest.

Written by the indexing model from the issue text.