JS Rewrite

[tjduigna]

Is your feature request related to a problem? Please describe.
The lagging JS dependencies for the notebook extensions are bad for long term maintainability. The JS should be modernized as much as possible and update to use current best practices in the build toolchain.

Describe the solution you'd like
I would like to see the JS ported to modern syntax with a reduction in code complexity and an easier to extend code surface area. I would like to see better defined interfaces

Describe alternatives you've considered
I tried this with the update-js-deps branch but it was not focused enough on retaining backwards compatibility and ran into its own problems with scope creep and poorly defined goals.

Additional context
I think #152 should be abandoned in favor of a more controlled approach with smaller merge requests which are easier to consume. I also would like to leave the original PR open for some time to use as reference.