RFC: Switch build backend to hatchling and use pyproject.toml

[PaulYuuu]

Modernize a setup.py based project by adding pyproject.toml, move package configuration to pyproject.toml, and also switch to hatchling as the build backend.

Refs: https://packaging.python.org/en/latest/guides/modernize-setup-py-project Signed-off-by: Yihuang Yu [email protected]