- Advertised user/groups that are generated by the pre scripts:
* package cephadm generates user/group cephadm
* package ceph-common generates user/group ceph

This is needed for RPM 4.19, as any %attr(, %user, %group) creates
automatically relevant use(%useR) and group(%group) dependencies.

Either users/groups are generated by sysusers.d snippets (and then
autodetected by rpm) or the package generates users as part of pre,
then the capability needs to be manually advertised.