Turn static throttling on in the live network

The feature is all implemented, and it works as far as we know. Some static throttling of super-loud clients would help free up the network for the rest of the users.

There are three parts to this ticket:

A) Get the directory authorities to add the right consensus params. And also decide what numbers to use. I think "perconnbwrate=50000 perconnbwburst=10000000" (i.e. burst of 10MB and rate of 50KB/s) would do it.

B) Before it can go live, we need to do something about the bwauthorities -- they suck down 64MB files from the fastest relays, and step A will throttle them, leading to confused results. The simplest hack I've thought of is to make them relays, and then they don't get throttled. (#9369 (moved))

C) Some way to measure if it's going right (general performance improves) or wrong (it's harming normal users). Ordinarily I'd be a big fan of getting all this infrastructure set up and doing an experiment, but that's going to take a year or more at this rate, and we could make a difference right now.