JupyterLab migration

[Jean-Noël Grad]

Dear all,

Today, the python branch of ESPResSo completed the migration of all 
tutorials to JupyterLab. Although you might still be able to use Jupyter 
Notebook to open and run most tutorials, we are no longer officially 
supporting Jupyter Notebook in the python branch.

To install JupyterLab, use the following command in the ESPResSo folder:
python3 -m pip install --user -c requirements.txt nbformat nbconvert 
jupyterlab

If you prefer the look and feel of Jupyter Classic (a port of Jupyter 
Notebook inside of JupyterLab), use the following command instead:

python3 -m pip install --user -c requirements.txt nbformat nbconvert 
jupyterlab nbclassic

You can then run ESPResSo tutorials using `ipypresso lab` resp. 
`ipypresso nbclassic`, depending on your installation.

These changes should be reflected in our online user guide tomorrow, 
after the automatic update from our nightly builds completes.

Please be advised that installing JupyterLab will update a lot of 
dependencies that are also used by Jupyter Notebook. One of our users 
reported that Jupyter Notebook stopped working due to conflicting 
dependency versions after installing JupyterLab. JupyterLab also updates 
the jinja2 dependency, which is used by waLBerla developers to generate 
new lattice-Boltzmann and advection-diffusion-reaction kernels.

Best,
JN