CC-2138 NZSL Upgrade Django 3.2.25 > 4.2

[jonholdsworth]

[CC-2138] NZSL: upgrade signbank to django 4.2 - Jira

[jonholdsworth]

Some things

• I've unpinned pretty much all the requirements.txt dependencies, as this is a large version jump and there didn't seem much point. Plus I hit some compatibility issues with the pinnings and was not about to waste hours/days. If there are any you think should be pinned for whatever reason please specify. Similarly, if you think I should release the remaining pinnings or update them.
• DATABASES is now a strict requirement. Somewhere around Django 4.1 -> 4.2 the requirement for this variable changed and its format became stricter. The Django docs are unfocussed around this. The short form is that collectstatic would not run in a local dev environment unless DATABASE_URL was defined - as this is used to create DATABASES - and DATABASE_URL is not defined that early. An alternative is make the setup define DATABASE_URL if it is not defined, instead of doing that for DATABASES. Whichever is felt to be neater.

[G-Rath]

this has also reminded me about moving to Poetry 😄 feel free to do that even before we land this PR if it'd make it easier

[G-Rath]

lets move to Poetry first

[jonholdsworth]

Reverting back to Draft until Poetry conversion completed.

[jonholdsworth]

And here we are in Poetry land.
Take a look, see what you think.