QF-4070 fix Delta Apply stuck in "Started"

[dddpt]

Fixed delta apply stuck in started, there were two cases in cron.py and wrapper.py. See clickup for detailed discussion of the error investigation.

In addition, I ensured error logs were more thoroughly downstreamed from jobs to deltas in DeltaApplyJobRun.after_docker_exception().

Do review thoroughly how I handled models update (especially in cron.py) as I am not super-familiar with Django models ;-)

[duke-nyuki]

Task linked: QF-4070 Delta Apply stuck in "Started"

[suricactus]

@dddpt I allowed myself to hijack this PR and apply a few fixes here, as we should not bother you too much these weeks.

@boardend I know this review request came out of nowhere, but I thought it is a nice opportunity to get familiar with the delta models. :)