Related #26984
(https://github.com/go-gitea/gitea/pull/26984#issuecomment-1889588912)
Fix admin cleanup message.
Fix models `Get` not respecting default values.
Rebuild RPM repository files after cleanup.
Do not add RPM group to package version name.
Force stable sorting of Alpine/Debian/RPM repository data.
Fix missing deferred `Close`.
Add tests for multiple RPM groups.
Removed non-cached `ReplaceAllStringRegex`.
If there are multiple groups available, it's stated in the package
installation screen:

The current rpm repository places all packages in the same repository,
and different systems (el7,f34) may hit packages that do not belong to
this distribution ( #25304 ) , which now supports grouping of rpm.

Fixes#25304 .
Fixes#27056 .
Refactor: [#25866](https://github.com/go-gitea/gitea/pull/25866)
The version listed in rpm repodata should only contain the rpm version
(1.0.0) and not the combination of version and release (1.0.0-2). We
correct this behaviour in primary.xml.gz, filelists.xml.gz and
others.xml.gz.
Signed-off-by: Peter Verraedt <peter@verraedt.be>