Migrate `setup.py` to `pyproject.toml`

[m-rph]

Task

Make the package compliant with PEP621, and provide project metadata in pyproject.toml over setup.py.

Rationale

Using pyproject.toml will make it easier to:

• manage dependencies as they will all be stored in a single file
• manage tool settings vs relying on flags in obscure make files
• enable poetry/rye/ other tools to manage the project and provide a more modern dev experience