Add a new directory authority: Nicholas Merrill

This ticket is to add Nicholas Merrill (#21914 (moved)) relay as a new directory authority. At this time, his candidate relay has been running in the test network for many months and Nick is working at transitioning it to the real network.

We've requested of Nick to also run a bandwidth authority.

Once Nick has completed the setup, he will be adding the needed information on this ticket so we can then create a DirServer line that current dirauth can add to their configuration.

Once that is complete and working, a config.c patch will be provided (GPG signed) and hopefully confirmed by others.

Putting in the 031 milestone and we'll handle the backport in time.