Some RIS collectors send updates days old while they catch up on a
backlog. Every update to a stored AS, peering or peer set last_seen to
the update's time, even an older one, and never lowered first_seen. An
AS page could then list a peer first seen after it was last seen.
The update statements for asns, peerings and bgp_peers now keep the
earlier of the stored and new first_seen and the later of the stored
and new last_seen, with MIN and MAX in the SQL. The batch and the
single-row writes share each statement. GetOrCreateASN returns the
times the row now holds. Route times are unchanged.
Model: opus-5-5
sneak