consider retiring build boxes
in the jenkins retirement (#40218 (closed)) we have decided to keep a few (three machines with debian_build_box, one of which is also a CI runner) build boxes with sbuild on it. even though we have retired Jenkins, which were its primary consumer, users like @weasel and @kez may still require those boxes for two use cases:
- @kez doesn't run Debian and might need a place to build random Debian packages not currently in GitLab (which could be fixed by moving those package builds inside GitLab)
- @weasel has a similar use case although he obviously runs debian, he also needs access to the ARM builder. it's unclear whether he still requires access to the build box in the long term or why (sorry, my memory fails me here)