Group TB (and CCC) inputs into an accordion menu

[MattHJensen]

Over at PSLmodels/Tax-Calculator#1074 (comment), @feenberg said:

Perhaps the TB web page could have expandable sections, where you could select a section to expose the parameters available to set, and perhaps subsections that could be expanded recursively.

This seems like a good idea to me too.

@talumbau and @brendancol, do you have any feedback before I add this to a milestone? Is there a relatively simple way to do this?

[MattHJensen]

After the accordion style is adopted for CCC and TaxBrain, when a user clicks "edit parameters", the sections that include modified parameters should be expanded (and the modified parameters should still conform to #459)