Has this feature been discussed and generally agreed?

Multiple discussions, e.g.
#1446 (comment)
No explicit agreement, as far as I know.

Describe the solution you'd like

The autobuild process should build arm binaries for Debian/Ubuntu as well.

Describe alternatives that have been considered

Make arm users (e.g. Raspberry owners) build themselves.

Last I checked, Github's native runners were x86-only. We may either have to cross-compile (not sure if it is possible without obstacles or how simple this would be) or we would need a self-hosted runner.

Possible cross-compiling approach:
https://github.com/multiarch/crossbuild