[Ci-users] new NFS export for RDO-store

Just to let the RDO people be aware that a specific nfs export has been made available for them on the artifacts node : artifacts.ci.centos.org:/srv/rdo-store (and will be accessible from n30.pufty.ci.centos.org)

The underlying LV is 250GB (as discussed) but can be grown later online if needed.