Add AmazonLinux 2023 to CI Pipleline

[kdvalin]

Summary

Adds Amazon Linux 2023 (both x86_64 and aarch64) to the CI pipeline and eventual publishing to packagecloud.

Changes

ci.yml: Add support for different arch's, since previously crun downloads were hardcoded to amd64 arch.
whatami: Detect /etc/amazon-release before defaulting to /etc/os-release

[kmcdonell]

@kdvalin My only real concern here is the change in ci.yml means everytime we run this workflow we're adding 2 more "hosts" for a full build and QA (check -g sanity) run.
If this fails for one of the amazonlinux2023 containers we're in a situation where none of the core developers use or can necessarily fix an issue specific to AmazonLinux.

Is there an option for including all of the other pieces of this PR, but doing your own thing for ci.yml?

If not, I'm happy to let this proceed, on the provisio that if it becomes a problem for the wider PCP project, we'll remove these lines from ci.yml until the issue is resolved.

[kdvalin]

Thanks for the feedback! I can separate out the ci.yml changes and move it to something like an experimental QA pipeline if desired. If it helps reduce some hesitations, AmazonLinux is essentially a stripped down Fedora (their repos don't include things like libvirt).

Ultimately what I'm looking for is the ability to install pcp rpms on AmazonLinux from PackageCloud, since my team is looking to utilize PCP to help standardize metric collection across multiple Distros (AmazonLinux being one of them).