pdm based build system pre-built wheels

[adehad]

Hi there @dgoeries

Sorry for the unsolicited pull request, I created this pull request to address #24 together with my own needs. Effectively I wanted to create pre-built wheels to reduce the install time and remove the MS Build tools dependency from my pipelines.

Summary of Changes

1. Build all the wheels in CI
2. Add windows to the list of os, so a pre-build wheel can be made (could also add macos too at some point)
3. replace tox (and also wheel) with a pdm based build system to reduce the number of tools needed
4. Run the tests in CI
5. The README.txt file was redundant as markdown support is now with pdm and also newer versions of setuptools

The final CI is like so, with a final wheels artifact that can be used to upload to pypi (although the https://github.com/pypa/gh-action-pypi-publish action would be a great way to automate the publishing in if desired):

Due to the retention period I have added this link to a successful CI might not show anything:
https://github.com/adehad/lttbc/actions/runs/8972532181

Future suggestions

1. It may make sense to make a separate CI config that only runs on tags which does all the wheel building, and perhaps only 1 python version and OS is used for every other commit