Switch to jupyter python distribution

ipython notebook is obsolete, replace it by jupyter.

This merge request consist of:

• adding jupyter component providing base jupyter software
• replacing inpython_notebook SR with jupyter one
• adapting ERP5 and Wendelin SR to use jupyter
• renaming ipython into jupyter respectively

TODOs:

• begin able to run ERP5Kernel
• assure that paths are correctly used and configured ( http://jupyter.readthedocs.io/en/latest/projects/jupyter-directories.html )
• being able to run python2 standard kernel
• as notebook_dir is not moved, no migration or manual steps are required for instances running older versions of Jupyter integration; nevertheless before merging this code checks shall be executed to assert no impact on data
• have custom.[js|css] information available for ERP5Kernel
• add folder for extensions https://lab.nexedi.com/nexedi/slapos/merge_requests/190#note_37030
• review by notebook users usability of new apporach ( ping Klaus & Tyagov when done)
• use scripts from zc.recipe.egg for explicity and control
• split some commits to small functional ones
• await for tests with Jupyter instantiation: ERP5-MASTER-slapos!190, status: Completed, FAILm the results are the same as ERP5-MASTER - also FAIL with 74 count