jenkins: Add PV/PVCs for backups

This creates a PersistenVolume and Claim for the backup routines. Note: these
aren't actually used for "backups" per se -- they're used for pod restarts to
ensure we keep the build history.

Committing this so we don't lose it to disk bitrot, and it's consistent with
what is currently loaded in K8S.

Change-Id: I4897900b91967538ac8d9f30ff85b4c0b21c50b3
1 file changed