Missing jupyter-cache dependency causes standard "Getting started" instructions to fail and import is seemingly unused

[lbianchi-lbl]

• In a fresh environment, running the following fails with a ModuleNotFoundError because of jupyter_cache:

  pip install idaes-pse idaes-examples[gui]
  idaesx gui

• The exception is raised here:

  examples/idaes_examples/build.py

  Line 40 in b791db5

  from jupyter_cache import get_cache

  However, the get_cache function imported from jupyter_cache is, to the best of my Ctrl-F abilities, not used anywhere