R1:1a6a0181a898

Allow "bin/repository thaw --demote" to demote an entire service, not just a single device

Summary: Ref T13222. See PHI992. If you lose an entire cluster, you may want to aggressively demote it out of existence. You currently need to `xargs` your way through this. Allow `--demote <service>`, which demotes all devices in a service.

Test Plan: Demoted with `--demote <device>` and `--demote <service>`. Hit the `--promote service` error.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13222…