The rhel8 package represented RHEL 8.3, which is EOL.
The current rhel86 package will be renamed to rhel8 and be responsible
for building all RHEL 8 minor versions.
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.
