Calculate weekly frequencies

[trvrb]

Rather than daily frequencies for raw_freqs use weekly frequencies instead.

With daily raw frequencies we have difficulty seeing patterns due to day-to-day measurement noise:

While with weekly frequencies, dynamics are much more clear:

This is the same argument for why 7-day smoothed cases were clearer to look at than daily cases.

[trvrb]

This PR has been updated to include both daily_raw_freq and weekly_raw_freq.