Sort out Celery settings

[Ed McDonagh]

Changes made in bd747f3 for Celery 6.0 weren’t implemented properly, meaning the tasks view fails (was still looking for old Celery uppercase setting, and lowercase settings are ignored by Django…

Use https://docs.celeryproject.org/en/stable/django/first-steps-with-django.html#django-first-steps to update to the approved method.

[Ed McDonagh]

Tidying up imports to views_admin; sort of refs #864 in that it is being done in that branch...

→ <<cset 0428b7e5a3f0>>

[Ed McDonagh]

Fixing Celery to v6 uppercase for Django. Refs #864

→ <<cset 9f8fa7c211e4>>

[Ed McDonagh]

Adding ref #864 to changes.

→ <<cset 5c55fe7c32a5>>

[Ed McDonagh]

Running Black on PR #418, refs #864.

→ <<cset 551d7bb8ffc2>>

[Ed McDonagh]

Merged in issue864celerysettings (pull request #418)

Refs #864

→ <<cset 601447f1ec51>>

[Ed McDonagh]

Closed in 601447f1ec51 PR #418