add example & docs for RubiconJSON

[ryanSoley]

Is your documentation request related to a problem? Please describe

since this is a completely new feature, we'll need a new section in the docs for it

Describe the solution you'd like

design a notebook showing how the new RubiconJSON class works (maybe just adapt the poc one we're basing this all off) for the documentation. add said notebook to the docs. add any new, public python methods to the API reference