Remove prominent link to defunct lightning project

[jbednar]

Visitors to https://nbviewer.jupyter.org will find a very prominent link to the lightning plotting package:

However, lightning is a dead project, according to the authors:

To avoid misleading people into a dead end, maybe you can remove the notebook:

https://nbviewer.jupyter.org/github/lightning-viz/lightning-example-notebooks/blob/master/index.ipynb

or at least not make it be featured as the first item in its category?

[parente]

Rev'ing the gallery is long overdue. I sent a survey to the Google Group around the time of JupyterCon 2018 polling the community for what they'd like to see on the frontpage. The survey only received a handful of responses and I failed market it further.

There's a related thread in jupyterhub/team-compass#181 about separating the gallery page from the notebook-rendering API of nbviewer. We should definitely coordinate with that effort.

As a quick fix here, perhaps we could choose from one of the repos/notebooks on the https://github.com/jupyter/jupyter/wiki/A-gallery-of-interesting-Jupyter-Notebooks page to replace Lightning alone. The LIGO analysis notebook perhaps: https://nbviewer.jupyter.org/github/losc-tutorial/LOSC_Event_tutorial/blob/master/index.ipynb

[krinsman]

This a related issue: #861

[JasonWeill]

Over 2 years later, this broken link is still on the NBViewer home page.