`ns info` displays registered time in local timezone

[slingamn]

As per #480 all times should be displayed in UTC. bogdomania reports that ns info displays a time in the server's local timezone: -Notice- {from NickServ} Registered at: Tue, 24 Dec 2019 21:30:51 EET. This is a minor information disclosure issue for Tor hidden services.

Later on we'll add a user preference for timezone.