Get rid of the jupyterlab dependency

[mwever]

• PyExperimenter version: 1.4.2
• Database provider: -
• Python version: -
• Operating System: -

Description

At the moment PyExperimenter requires a dependency on jupyterlab. However, I do not see why this should be the case (except for test examples in the repository maybe). Jupyterlab comes with some serious stack of recursive dependencies impeding py-experimenter's lightweightness.