DB and RQ backends are now external

[RealOrangeOne]

I've seen many people be confused about django-tasks, django.tasks and the state of the ecosystem.

To make this clearer, starting with 0.12.0, the database and RQ backends have moved to their own repositories.

• https://github.com/RealOrangeOne/django-tasks-db
• https://github.com/RealOrangeOne/django-tasks-rq

Both are available on PyPI and ready to be installed and used.

Now, django-tasks exists purely as a backport for django.tasks functionality in older versions of Django. The database backend is now separate. The intention is still to eventually include it in Django itself (:crossed_fingers: ), but this clarifies that is is separate from the django.tasks interface, and that other backends can and should exist.

As a result of this, and because much of this code is already in Django itself, the state of this package has been upgraded to "Production / Stable" 🥳

As mentioned in the contributing guide, discussions about the future of django.tasks can absolutely happen here. However, notable changes will need to be upstreamed into Django first before being included here.

[RealOrangeOne]

I've written up a bit on how I extracted the backends out, for those interested: https://theorangeone.net/posts/git-directory-extraction/