F42: Investigate RPM sysusers change (adapt Zincati RPM to it)

[travier]

See: https://fedoraproject.org/wiki/Changes/RPMSuportForSystemdSysusers

We should make sure to adapt all the packages that we maintain to make use of the feature.

For now, that should be only Zincati .

[travier]

It looks like the migration to sysusers is going to happen globally in Rawhide soon:

• https://lists.fedoraproject.org/archives/list/[email protected]/thread/BHYVPXSLZHFESM4AFXWM4ZDPBUFLEFGG/
• https://fedoraproject.org/wiki/Changes/RPMSuportForSystemdSysusers

[jlebon]

Is there anything to actually do for Zincati here? We already ship a sysusers dropin and we don't currently generate a user for it at compose time. This proposal helps with creating users from sysusers dropins at RPM transactions, but we don't want that here.

AIUI, this proposal doesn't really unblock anything for image variants, but it does overall help in the sense that it makes sysusers more widespread.