Revoking a host now unassigns its instances instead of being refused
while it has any, and removes its system metrics.
Approving and revoking no longer force a save. Hosts are saved by
autosave and on exit like everything else, which also removes the
approving state from pairing requests.
The approval code and link are logged as warnings so they show up in
the systemd service, which only prints warnings and above. The pairing
limits are now the controller.host_pairing_timeout and
controller.host_pairing_max_pending config values, 0 removes the limit.
Subscribers take an optional permitted function, used for the pairing
requests instead of overrides in a subclass.
Danielv123
49a0b27d29