Jython support

[pradyunsg]

Coming from pypa/pip#10202, where we noticed that there's no analogue to appdirs.system -- which seems to exist primarily for Jython support.

https:/ActiveState/appdirs/blob/8eacfa312d77aba28d483fbfb6f6fc54099622be/appdirs.py#L27-L40

It might be worthwhile to exploring what to do here.

[Julian]

This may be slightly tedious since actions/setup-python doesn't know how to install Jython (actions/setup-python#39) but we can probably give it a shot the old fashioned way.

[gaborbernat]

Considering the very low adoption of jython and endless bugs it provides I'd rather not add it to the CI and just validate with a simple unit test support for it 👍

[domdfcoding]

I removed the system attribute while dropping Python 2 support as part of #14. At the time jython only supported Python 2, and I think that's still the case.

[pradyunsg]

It might be worthwhile to exploring what to do here.

Python 2

LOL. I'll defer to the maintainers, but feel free to close this. :)

[Julian]

:D hooray for WONTFIX. Sounds good.