django3

The major change change for this merge is the upgrade from django-2.2 to django-3.2. Note that this does require a db migration after the upgrade.

Secondary to the django upgrade were changes in how messages were published to the lvalert-overseer (to facilitate integration of the igwn-alert-overseer). There were some pipeline and Docker changes to support this. The medium-term plan is to spin it off into a separate containerized service, but that is still in progress.

There is also a version bump. Currently tagged 2.12.1 containers are running on test and playground, but I haven't seen errors so far.

Edit: This is now just django3.