Licensecheck

- Add html output using `markdown` lib https://github.com/FHPythonUtils/LicenseCheck/issues/77

- fix critical TypeError: can only join an iterable

- fix critical https://github.com/FHPythonUtils/LicenseCheck/issues/75 where importlib.metadata.PackageMetadata.json does not exist in Python < 3.10

txt
py311: OK (7.55=setup[5.89]+cmd[1.66] seconds)
py310: SKIP (0.02 seconds)
py39: SKIP (0.02 seconds)
py38: OK (6.23=setup[4.30]+cmd[1.94] seconds)
congratulations :) (13.95 seconds)

- fix https://github.com/FHPythonUtils/LicenseCheck/issues/74
- update tests (as env has changed, ideally we'd mock more than we do atm)
- linting fixes

- fix: use `appdirs` for storing the db for `requests_cache`

- Update Matrix for AGPL_3_PLUS