Add ARM64 build support

[Firefishy]

DRAFT - Not yet ready. Preview.

matchhostfsowner is not yet available for arm64, needs own PR.

[Firefishy]

@FooBarWidget I'd appreciate any feedback. This is more complex than I initially thought. Happy to re-organise based on your comments.

[FooBarWidget]

Thanks, I'll have a look as soon as I can.

One important caveat is that I'm not sure whether our APT and YUM repository design scales enough to be able to accomodate ARM64 packages. Introducing ARM64 would roughly double the amount of packages we need to store, and we are already approaching scaling limits now, most notably Github CI runner disk space. In the worst case we'll have to redo the APT and YUM repository design, maybe even write custom APT/YUM repo generation tooling, to be able to handle this.

[Firefishy]

PR for creating ARM64 builds of matchhostfsowner

[FooBarWidget]

Hello, I want to let you know that I haven't forgotten your request. I have done my upmost best in the past month to allocate time, but it just doesn't work out. Between needing to take care of spouse, children, parents, and health issues, I just can't do it. My health is not cooperating and I can't push myself that hard anymore. There are too many obligations and not enough time and health points. I'm afraid that for now I have reached the limits of what I can do.