A missing snapshot could cause an exception here which would break the
entire autobackup run. Catch the exception and continue on as this
should never be a fatal situation.
It was far too cumbersome to report every possible stage here in a
consistent way. Realistically, this command will be run silently from
cron 99.95% of the time, so all this overcomplexity to handle individual
Celery state updates just isn't worth it.
With the original system, the failure of one VM's backups would not
trigger a total fault, thus allowing other backups to complete.
Restore that behaviour.
Avoid trying to subcall other Celery worker tasks, as this just gets
very screwy with the stages. Instead reimplement what is needed directly
here. While this does cause a fair bit of code duplication, I believe
the resulting clarity is worthwhile.
Moves VM autobackups from being in-CLI to being handled by the
pvcworkerd system on the primary coordinator. Turns the CLI autobackup
command into an actual API client endpoint rather than having its logic
in the CLI.
In addition, modifies the new autobackup to leverage the new "pvc vm
snapshot" function set, just with special snapshot names. This helps
automate this within the new snapshot scaffolding.
