Support aarch64-linux hosts

[lilith]

Checklist

• I've looked through the issues and pull requests for similar request
• This feature could be solved with a custom image (optional)

Describe your request

Creating aarch64-musl builds - and testing them - is very useful. Github actions supports custom runners for Ubuntu 22/24 aarch64. However, I can't run cross on that platform (as far as I can tell, using CI-ready binaries).

Using QEMU for integration tests is a bit slow. Would aarch64 support be difficult?

Describe why this would be a good inclusion for cross

Creating aarch64-musl builds - and testing them natively - is very useful.

[Emilgardis]

I agree! This is actually already supported, it's just that we lack the images. See #751 where I have some examples of this working

Duplicate of #751