Get project factory failure rates

Counts the finished runs of the project's Loops created in the requested window (filter[timestamp][gte] to the exclusive filter[timestamp][lt], at most 90 days, the last 7 days when neither is given) and in the window of the same length just before it, and how many of them failed, by cause. series has one point per UTC day that the current window touches, with its finished and failed runs and zeros included, so the points add up to current.