Add RPM and AUR packaging support

[loriopatrick]

Summary

• Add Fedora/RPM packaging to release builds, including per-architecture RPM assets for x86_64, aarch64, armv7hl, and i686.
• Add an Arch Linux AUR package generation flow and publish playit-bin-PKGBUILD.tar.gz as a release asset.
• Refactor Linux packaging into shared staging and metadata helpers to reduce duplication across .deb, .rpm, and AUR outputs.
• Update the README and release download script to cover the new package formats.

Testing

• Not run: release workflow validation in GitHub Actions.
• Not run: RPM package install/upgrade/remove on Fedora.
• Not run: AUR package generation with makepkg/namcap.
• Not run: Debian packaging regression check after the shared staging refactor.

[sje0dev]

is this still on progress?
Otherwise i would do this pr

[Techcable]

For the AUR repo, if you don't get a response from the maintainer of a package and they are not updating it, you can submit an "orphan" request to take over the package.

Note that by AUR policy, the "playit" package must compile from source and cannot use downloaded binaries. Using precompiled binaries is only allowed for the "playit-bin" package.

This information comes from the AUR Submission Guidelines Wiki Page.