Revisit developer dependencies and prune down requirements-dev.txt

[lbianchi-lbl]

• Even though we're still working on reproducing the issue, Issues with developer installation with "Failed to build jupyter_contrib_nbextensions" error #1529 seems to be caused by jupyter_contrib_nbextensions erroring out during installation, preventing the rest of the packages (including idaes-pse itself) from being installed
• jupyter_contrib_nbextensions is part of the developer dependencies in requirements-dev.txt, but it's not clear (1) why it was originally added, and (2) whether we still need it
• From a quick look, the same can be said of other dependencies in requirements-dev.txt

Because of this, I think we should look through requirements-dev.txt and get rid of all the dependencies we're not using.