vdf docs: add backup locations
vdf docs: add backup locations

Also change the backup interval to be 12h because that's how it is
currently set up.

kubernetes/k8s.io,thockin/k8s.io,kubernetes/k8s.io,thockin/k8s.io,kubernetes/k8s.io,kubernetes/k8s.io,thockin/k8s.io,thockin/k8s.io