update packaging

[12rambau]

As my question (#1130) may seem tedious I decided to look at the packaging file from both ipyvuetify and ipyleaflet to understand how the css and js dependencies are created and injected.

The consequence is that I also spend some time refactoring the packaging for them: widgetti/ipyvuetify#259 and I also did some small modification here:

• move all information from septup.py to pyproject.toml to modernise and centralize the configuration.
• only keep the cmdClass in setup.py

Help needed:

• pyproject.toml need to include the version parameter and cannot read python files to guess it. how do you want to proceed for its update ? rely on external tools like commitizen ? create a small script in the release pipeline ?
• there are still deprecation warning in the setup.py file but as I fail to understand exactly what is happening there I'm not sure what to do. any guidances would be much appreciated.

Let me know if it make sense for me to work on this or if it's simply not wanted.