Revisit ARM64 image support

[phlogistonjohn]

In PR #180 we did a bunch of stuff to build arm images in the CI and then the work on arm64 images kinda petered out. This was partially my fault as I planned to make #191 a big part of the arm image story but never got back to that PR.

But with the release of Ceph tentacle, Ceph users on arm are also looking to try SMB support out: https://lists.ceph.io/hyperkitty/list/ceph-users@ceph.io/thread/3IRN7PJ66IAUTOI4GVQDD3Q7VO2YTEQJ/

It would be good to resume working on this ARM64 support esp. now that we should have real arm support in centos ci and github actions.

We should at least aim to have arm images for the fedora based image and ceph images.

[synarete]

@phlogistonjohn For ceph+smb to work properly on ARM64 all other smb containers (e.g. smbmetrics) should also provide arm based images. Please let me know when the relevant PR is ready for review.