Use the django_mailman3 context processor

Use Django-mailman3

Use the new django-mailman3

Update readme

Fix urls for example project

Update requirements for example project

Make the example settings closer to the old standalone settings

Use a specific settings files for testing

Restore mailman.cfg

Update gitignore and requirements

Update example_project to not log by default

Update urls

Use example project to run tests

Update example project settings

Rename example project