add pyproject.toml and tox to make testing simpler

[pgammans]

I realise that you may not want to modify you curent build process, but i am using this to help speed up my testing of changes, atm this is focused on getting Django 4.2 to work and pass all tests. But though this may be of general value.

This PR:

• Moves to using add pyproject.toml instead of setup.py.
  Currently this is using the git tag to set the version
• Add a tox file so it is simple to run all the test against different version of python and Django
  I have a version of this that includes django 4.2 in which tox fails to build but this is also not in the currently tested set
• Updates the target version of py and Django to match
• Add a test coverage report

[millerdev]

@pgammans it looks like most of the tests failed. Are you intending to do more work on this PR?

[pgammans]

Hi
I am happy to do more work on this, but i didn't want to unless there was a chance you would accept it as it was a change to the current build process and that the remaining work is in the github pipeline.

All the test pass locally when you run
tox
the core issue is in the GITHub pipeline not building the version file, setuptools should build this automatically for us but as yet I've not investigated why, it is probably a simple fix.

ATM, The version ID is pulled from the GIT tag on the branch, again if this isn't something you like i can remove it but it allows me to inject a build ID into the version in our internal pipeline when we build in azure or allow us to have dev version.

[pgammans]

Ok, after a few! tries I have a version of the github pipeline that works.
I'm not sure how you build a release and if these changes will affect that so, there may be some work there needed.

This also updated to pynose for the tests as this is needed for py 3.10.
I have not as yet updated the readme file to reflext we can test by just running tox, especially useful if you have pyenv installed