create and configure `pyproject.toml` file

[aqw]

Originally reported in #569

When installing onyo via pip:

Installing collected packages: onyo
  DEPRECATION: onyo is being installed using the legacy 'setup.py install'
  method, because it does not have a 'pyproject.toml' and the 'wheel' package
  is not installed. pip 23.1 will enforce this behaviour change. A possible
  replacement is to enable the '--use-pep517' option. Discussion can be found
  at https://github.com/pypa/pip/issues/8559

Some upstream guidance:

• https://packaging.python.org/en/latest/guides/modernize-setup-py-project/
• https://packaging.python.org/en/latest/guides/writing-pyproject-toml/
• https://github.com/pypa/pip/issues/8559
• https://peps.python.org/pep-0517/