We modelled our VFS clientset (for API objects backed by a VFS path)
after the "real" clientsets, so now it is relatively easy to add a
second implementation that will be backed by a real clientset.
The snafu here is that we weren't really using namespaces previously.
Namespaces do seem to be the primary RBAC scoping mechanism though, so
we start using them with the real clientset.
The namespace is currently inferred from the cluster name. We map dots
to dashes, because of namespace limitations, which could yield
collisions, but we'll deal with this by simply preventing users from
creating conflicting cluster names - i.e. you simply won't be able to
create a.b.example.com and a-b.example.com