moves python2 release to component/jupyter-py2 because it is required by ERP5
but not maintained anymore

moves to python 3 :
- test/test.py
- jupyter_notebook_config.py.jinja
- ERP5kernel.py

modifies custom.js to create a workaround for events issue
see (https://github.com/jupyter/notebook/issues/2499)

upgrades slapos.cookbook version to 1.0.171 to use zero_knowledge recipe
with python 3

adds jupyter partition check in software/erp5/test/test_erp5.py

Added password generation and monitoring to jupyter instances. Todo: Password editing at the monitor.

A redo of [this](nexedi/slapos!148) merge request. I messed up with some merge conflicts on the old one and thought it would be faster to make a new one...

@alain.takoudjou  @Tyagov 

/reviewed-on nexedi/slapos!156

/reviewed-by @kirr  (on nexedi/slapos!33)