Update Commitfest requirements and README

Hello,

While trying something out on the Commitfest, I found that the README
and the dependencies are quite outdated. It still requires Django 1.8,
as example.
And a couple modules are missing, which are not listed in the dependencies.

Attached patch takes a first shot at this problem, updates dependencies and
README to Django 3.2 and adds all missing modules (so far).

This brings the website into a state where it at least starts.
But then when I try to login, I run into this error:

'Settings' object has no attribute 'PGAUTH_REDIRECT'

Apparently the example settings for /local_settings.py/ are incomplete.

Thanks,

--
Andreas 'ads' Scherbaum
German PostgreSQL User Group
European PostgreSQL User Group - Board of Directors
Volunteer Regional Contact, Germany - PostgreSQL Project