Use single NewGroupsStageOptions() from osbuild1 and osbuild2 instead of
implementing in each distro.
- Followup from 2eef6e6e2d, copied to the
rest of the RHEL distro definitions.
- Added NewGroupsStageOptions() to osbuild1 for rhel8 and rhel84.
NB: The change was not made in the Fedora distro definitions as they are
currently being rewritten.
Use entity based method `ForEachMountable` and `getDevices` to generate
all mounts and devices in a generic way, which then allows for mounts on
arbitrarily nested devices.
Update manifests and image info:
- New device names generated by `pathdot()` to avoid basename
collisions.
- Some partitions are generated in a different order now which changes
the order they appear in the manifest and their UUIDs.
Co-Authored-By: Christian Kellner <christian@kellner.me>
