[ENH] move to pyproject.toml

[Moritz-Alexander-Kern]

This PR moves Vizipahnt from setup.py to pyproject.toml, aligning with PEP 518.

Key changes include:

• Introduction of pyproject.toml
• removed setup.py, since it is no longer required

See also: https://github.com/NeuralEnsemble/elephant/pull/608