Create newton-notebook output

[diegoferigo]

This PR adds a new newton-notebook output to the newton package. From:

• newton v1.1.0 newton-feedstock#2

Checklist:

• I want to add a package output to a feedstock:
  • Pinged the relevant feedstock team(s)
  • Added a small description of why the output is being added.

[diegoferigo]

@conda-forge/core, ready for review!