Make it easy for users to see what data is currently available clean for each jurisdiction

[sfsinger19103]

Last time I checked, some of your datasets were works in progress, rather than complete. It would be great to have a resource that a visitor to the repo could find, detailing exactly what is available completely -- for each state, district, territory, and for each election:

• what contests results are available?
• at what geographical level?
• are vote types (e.g., election day, by-mail, vote-center) broken out?
• is cleaning & checking complete?