This adds support for parsing static UIDs and GIDs from sysusers.d
fragments, and automatically forwarding them to the generated
'Provides' entries.
It will allow inspecting users/groups with static IDs directly
from package metadata:
```
$ rpm --query --provides --package gdm-41.0-3.fc36.x86_64.rpm
[...]
group(gdm) = 42
user(gdm) = 42
```