Avoid duplication in Interop-data.json?

[gsnedders]

webapp/components/interop-data.js and webapp/static/interop-data.json both contains a decent amount of duplication.

I wonder if it would make sense to move the categories to having a singular definition, and then each year merely lists scored and unscored categories? It would also allow us to guarantee that category identifiers are unique and stable, which would probably be a longer-term win — because it also means we only need to calculate the score once per category in results-analysis.

cc @DanielRyanSmith @jgraham