All hosts are now running thier backups via borg to servers in
vexxhost and rax.ord.
For reference, the servers being backed up at this time are:
borg-ask01
borg-ethercalc02
borg-etherpad01
borg-gitea01
borg-lists
borg-review-dev01
borg-review01
borg-storyboard01
borg-translate01
borg-wiki-update-test
borg-zuul01
This removes the old bup backup hosts, the no-longer used ansible
roles for the bup backup server and client roles, and any remaining
bup related configuration.
For simplicity, we will remove any remaining bup cron jobs on the
above servers manually after this merges.
Change-Id: I32554ca857a81ae8a250ce082421a7ede460ea3c