Backfill pageview data

[audiodude]

We need to backfill the pageview data. Let's go with past 2 years for now, we can backfill further later if it seems necessary.

This depends on #761 and probably requires a bit of management of the scores.py script so that it can be run for specific months, plus maybe a one-off shell script to run it consecutively and print success/failure messages.