Graph consensus and vote information from Rob's experiments

This is a ticket for the work to graph the historical onionperf data from Rob's relay flooding experiment.

Some discussion threads: https://lists.torproject.org/pipermail/tor-scaling/2019-December/000077.html https://lists.torproject.org/pipermail/tor-scaling/2020-January/000081.html

Basically, we want to have a standard way to graph results from key metrics from before, during, and after the experiment.

In this case, we want CDF-TTFB, CDF-DL from onionperf results.

We also want CDF-Relay-Stream-Capacity and CDF-Relay-Utilization for the consensus, as well as from the votes, to see if the votes from TorFlow drastically differ from sbws during the experiment.

https://trac.torproject.org/projects/tor/wiki/org/roadmaps/CoreTor/PerformanceMetrics

Update from June 10, 2020: We finished the CDF-TTFB and CDF-DL portions by adding these graphs to OnionPerf's visualize mode. The remaining parts are the CDF-Relay- graphs that are based on consensuses and votes. Keep this in mind when reading comments up to June 10, 2020.*