pyright support

As mypy and pyright are rather close in what they do and how to use them: would it be possible to extend rules_mypy to pyright? More specifically basedpyright - or both.

Some obvious points I can see:
* Passing config via `--mypy-ini` parameter vs implicit `pyproject.toml` or `pyrightconfig.json` file in the root. Might be fine if `pyproject.toml` is simply added to srcs instead.
* No `--output` flag
* No `--cache-dir` flag -> should be fine by leaving cache = false
* No `--upstream-cache`
* Different py_binary

Start by reading the existing rules_mypy implementation and tracing how it handles --mypy-ini, --output, --cache-dir, --upstream-cache, and py_binary. Compare those entry points with pyright and basedpyright configuration via pyproject.toml or pyrightconfig.json; done means the supported checker can be selected with the stated configuration differences accounted for.

Written by the indexing model from the issue text.