Transition from Jupyter to Jupyter-lab

[RemiLehe]

As Jupyterlab becomes more prevalent, we should update the package to use Jupyter lab primarily. This implies:

• Downloading jupyterlab instead of jupyter when installing the package (including with conda-forge)
• Updating the default command that runs when doing openPMD_notebook
• Changing the command %matplotlib notebook to %matplotlib widget in the default notebook

[ax3l]

X-ref:

• %matplotlib widget use %matplotlib widget by default #407 More %matplotlib widget in comments #414
• sidecar Slider: sidecar option #415