Make project PEP 518 compliant by using pyproject.toml and only declarative configuration

[DavideWalder]

Is your feature request related to a problem? Please describe.

• The project doesn't use a pyproject.toml to specify the build system, see: https://setuptools.pypa.io/en/latest/userguide/quickstart.html#basic-use

• The project is built using setup.py instead of setup.cfg or pyproject.toml, see here for the rationale

Describe the solution you'd like Move the content of setup.py to pyproject.toml

Describe alternatives you've considered

Additional context

I had a look at the project to try to understand why setup.py is being used but couldn't find any.

Also, tools such as pytest, formatters and so on support pyproject.toml. The general direction is to only use this file for configuration (the TOML parser was also included in the standard library in Python 3.11)