Add Stubs for Python Interface

[max-muoto]

This PR adds public facing type stubs to improve usability to give Python users intellisense and the ability to use minininja in projects with type-checking enabled. Pyright is used for basic linting/ensuring these stubs are valid across all versions of Python minijijna supports (3.9+).

If this isn't something you're interested in maintaining for the time being, I'm happy to just put this on typeshed instead.

Also fixes #572

[mitsuhiko]

I think this is probably a good idea to add but the question is how to make sure it stays up to date and correct.

[max-muoto]

I think this is probably a good idea to add but the question is how to make sure it stays up to date and correct.

I think we could try out using Stubtest and see if it would allow us to at least have some basic level of correctness (making sure the we don't miss any new functions/leave old stubs around). Any thoughts?

[mitsuhiko]

I would like to include this but the pyright CI step fails.

[max-muoto]

I would like to include this but the pyright CI step fails.

If you're able to approve the pipelines again, I think things should be working now.