Remove enabled 3rd party extensions in notebooks and migrate them to config file

[jtmiclat]

Having conditional enabling extensions is a code smell. Extensions should be optional for users. We can add a config file that enables it for dev and disable it for end users https://ipython.readthedocs.io/en/stable/config/extensions/#using-extensions https://jupyter-notebook.readthedocs.io/en/stable/config.html

[butchtm]

Ok! ref #85