feat: add covid hospitalizations production pipeline

[dshemetov]

Fix #39. Took a while to get the metaprogramming bits right. A few smaller details left:

• plotting notebook
• need to double check that we're using the right forecaster with the right params

Roll out plan:

• clone this on the production machine
• set a cronjob to run this targets pipeline ahead of the legacy pipeline
• read the targets object directly in the daily pipeline and integrating it into the plotting
• once we're convinced it can be used to replace the existing pipeline, we can deactivate the legacy pipeline and migrate the other bits here (plotting, slack posting)

[dsweber2]

Generally looks good! There's a range of things, but the only hold-ups are the things I actually made suggestions on, and how to handle the exclusion date.

Not sure how seriously to take plotting specific problems, if we're actually just using the results in a different place for now.

[dsweber2]

should've said approved earlier