Add Flask example

[rsyring]

Django has a WSGI example. I know quart is intended to be essentially Flask with asyncio so easily translatable. But would be nice to just have a plain Flask WSGI example.

Thanks for considering. :)

[gazpachoking]

So, I would almost certainly not pick flask for a new project. Perhaps there is value in showing how it would be done though.

[rsyring]

Even so, Flask is arguably the most popular Python framework:

https://blog.miguelgrinberg.com/post/a-year-in-review-flask-in-2024

[gazpachoking]

If anyone wants to take a crack at it we can add it in.