data: add minimal record for CentOS Stream 9
This provides the bare minimum record for CentOS Stream 9, with data copied from CentOS Stream 8. All media and all treeinfo records except the generic one are removed, since nothing is officially published yet. This record is good enough for virt-install to be able to do the right thing when launching the CentOS Stream 9 installer.
Signed-off-by: Daniel P. Berrangé berrange@redhat.com