[Feature] RPI support

[kfox1111]

I've been running AlmaLinux on 6x RPi 5's using bootc for a while now. Looking to upstream the bits so I can start integrating easy to build / release RPi based bootc images into various projects. Having easy to extend images from Alma would go a long way.

[kfox1111]

An outstanding question is how it will integrate with the build system here and the tags used.

Will it show up as a variant in #36 once it merges?

Also, what will the tag for the rpi images look like. prefix rpi? suffix?

[alexiri]

A build for RPI 5 would be the arm64 build with some different repos, right? I'm not sure if that should be a here or a separate repo, but that's probably a question for the Cloud SIG.

[hanthor]

Yeah rpi seems like a derivative image. We can just add packages via a FROM the base image

[hanthor]

If reducing the number of layers is important we can fork this repo to make RPI specific builds

[kfox1111]

Its not just repos, but Kernel/Initrds. So it could add quite a bit of overhead.

[imbev]

Depending on the complexity, it might be worthwhile to keep it within this repository. Do you have an existing repository that we can reference?

[kfox1111]

@imbev please see #27