Update moat domain fronting configuration

The front we're currently using for moat (foursquare.com) renewed its certificate today, which brought into effect Fastly's new policy to match the Host header to the cert SANs. Moat won't work until we update the bridgedb_front and bridgedb_reflector prefs. We're discussing what the new domain fronting configuration should be in tpo/anti-censorship/team#135 (closed)