Dir auths using an unsustainable 400+ mbit/s, need to diagnose and fix

We've been having problems establishing a consensus lately. We realized that maatuska was rate limiting to only 10MBytes/s, and asked Linus to bump it up, so he did.

Then today we realized that moria1 was unable to serve dirport answers because it was maxed out at its BandwidthRate of 30MBytes. I raised that to 50MBytes and it stayed maxed out. I have put it back down to 30MBytes so my host doesn't get too upset.

This is not a sustainable situation. We need to figure out what is asking the dir auths for so many bytes, and get it to stop or slow down.

This is a ticket to collect info and to brainstorm ideas.