Print job statistics on '!status jobid' after completion

[JustAnotherArchivist]

After job completion, !status $jobid prints very little information. It would be useful to also have total size, number of responses and errors, and perhaps some other metrics available, e.g. for a quick check whether a job did something sensible without having to keep the dashboard open 24/7.

I think the data doesn't get removed from Redis when the job completes, so it should simply be a matter of adapting the !status response.