cephadm bootstrap: add --apply-spec <cluster.yaml>
to have truly a single command when setting up a cluster for Day 1
- YAML spec for hosts similar to `ceph orch host ls --yaml`
- ceph orch apply -i # also accepts host yamls
Either assume that the current user/shell can run the ssh-copy-id command without getting a password prompt.
Or also allow setting a ssh config via --ssh-config <filename>