Add nbstripout to the repo

[bvarjavand]

https://github.com/kynan/nbstripout

[bvarjavand]

This allows for docs to build them, and for simpler diffs and git contrib

[bvarjavand]

Currently: Every time someone pushes a jupyter notebook with output, documentation simply loads the notebooks instead of rerunning them.

A solution is to use nbstripout to remove notebook output when pushing.

"working notebooks" that are used for debugging or for presenting in meetings should not be located in this repository.