Incompatibility with nbsphinx

[calebrob6]

(duplicating spatialaudio/nbsphinx#599)

When including nbsphinx with pytorch_sphinx_theme several components of the theme break:

• Permalinks to sections are hidden
• The right (mobile) sidebar navigation expand/collapse buttons are hidden / don't work
• The right (mobile) sidebar navigation doesn't scroll with the page and instead is stuck on the top of the page

nbsphinx uses requirejs which conflicts with bootstrap 4.0 (used here). We found the solution was to simply disable requirejs, however this will prevent nbsphinx widgets from working (not a problem for us at the moment).

@mgeier helpfully pointed out that pydata-sphinx-theme has solved this type of problem by including their js dependencies "UMD style" -- pydata/pydata-sphinx-theme#167. Is this something that would be possible to do here?