R1:2a7ac8e3882f

Make "bin/repository thaw" workflow more clear when devices are disabled

Summary:
Ref T13216. See PHI943. If autoscale lightning strikes all your servers at once and destroys them, the path to recovery can be unclear. You're "supposed" to:

- demote all the devices;
- disable the bindings;
- bind the new servers;
- put whatever working copies you can scrape up back on disk;
- promote one of the new servers.

However, the documentation is a bit misleading (it was sort of written with "you lost…