Better communication for authority operators, core developers in emergency situations

When in danger or in doubt, run in circles, scream and shout!

• traditional motto, possibly naval.

When the bug behind #2664 (moved) happened, it took us a few hours to notice. That was bad, and #2666 (moved) is about trying to notice such situations faster. But another problem is that even after we noticed, it still took a while to sort out who knew how best to contact which operators. Probably developers should get contacted too, so they can be available to deal with bad/urgent bugs.

We should figure out, for each authority operator and core developer[*], the best two or three ways to contact them in the case of an emergency. If these ways are not something we want to publish (e.g., phone numbers), a few people should know them, and all Tor people should know who those people are and how to contact them in a hurry.

We should have some emergency-response mechanisms in place. If communications are security-sensitive, we should have a way to deal with it in place, rather than the current approach of "send gpg-encrypted email to those people whose keys you happen to have" or "immediately go dark, use OTR to talk pairwise to people you know". Those approaches scale badly; we can probably do better.

We should also have planned responses for emergency events like "A key server looks like it might have been compromised"; "somebody has reported a vulnerability"; "somebody has disclosed a vulnerability"; "one or more authorities have gone down strangely;" "looks like the network is crashing;" and so on.

[*] "core developer" is here defined as "a developer who is likely to needed urgently when something breaks."