Upgrade Django from v2.2 to v3.2 LTS

[aufdenkampe]

We should upgrade to Django 3.2 LTS by April 2022.

With PR #501 we upgraded Django to v2.2. See:

• Upgrade Django from v1.11 to v2.2 #385

Unfortunately, Django 2.2 LTS end-of-life is April 2022.
Django 3.2 LTS was released in April 2021.

Here's What's new in Django 3.2 LTS compared to 2.2 LTS.

The main feature of Django 3 is support for ASGI (Asynchronous Server Gateway Interface), which is a successor to Python WSGI (Web Server Gateway Interface). Let's explore ASGI when we work on #431.

[ptomasula]

@aufdenkampe

I started us down this path. Commit 7fb62dd updates the refactoring branch to 3.2.11, which is the LTS version of Django. The application builds fine, but there is still more testing needed before I'm ready to call us updated and close out this issue.

[ptomasula]

We've been testing the Techdebt-refactoring feature branch with Django LTS 3.2 and python 3.9. I've update the environment.yml file to reflect this. We'll be on this tech stack once we do our next scheduled release.