Make current model more automatable

[sam-writer]

I was hoping to loop over the function in order to generate SIR output (not necessarily markdown, just numerical output) for several different jurisdictions/hospitals 'at once' without having to use the GUI. i mentioned this above and was pointed to models.py, but it doesn't have the super useful extensions available in app.py. In a thread above, it was recommended to do a fork and dev, but that's a bit beyond me at the moment. Worst case we just run this by hand for all our jurisdictions, but will likely be asked for daily report / simulation testing, so was hoping to automate
the dataframes that generate the charts would be priority (from which i could compose outcome metrics of interest), and the visuals themselves would not be necessary (but a perk!)
src

This is a matter of better encapsulating the modeling code.

[machow]

Hey! I told @quinn-dougherty I could quickly refactor some of the app logic to live in a class, that goes essentially from <parameters currently entangled in UI> -> a plot

This might also be a good first step for people experimenting with moving away from streamlit, since with this setup, streamlit will essentially just be the view-model

(Taking 30 minutes to do now)

[quinn-dougherty]

CLI in #170

[quinn-dougherty]

i think between recent modularization and the CLI and the scope of this issue, we can close.