Visualize Torperf data as quantiles of moving windows
Our current Torperf graphs show the daily median and quartiles of download times. This is fine for plotting intervals of a few weeks or more. But sometimes we want to plot Torperf data of a few days or even a single day (#2476 (moved)). In these cases we might want quantiles of shorter time periods or, possibly even better, of moving windows. We might replace the graphs on the website with these new graphs, but more importantly we should have the code available for making custom graphs. Related to #2519 (moved) and #2563 (moved).