Expand to other pathogens

[AdvancedCodingMonkey]

There's a 'frequencies' app by Neher lab that does flu (and in the works, some other stuff) (github) -- we'd need a longer convo to talk about the differences and complexities here but in theory it might be nice to align with them so that CoV plots could eventually be shown on this page, and in theory maybe we could both expand to other viruses