Go through all the routers once, after startup, and refetch their router infos.
This should be run once after startup (and preferably after any reseed is complete,
but we don't have any indication when that is).
This will help routers that start after being shutdown for many days or weeks,
as well as newly-reseeded routers, since
validate() in KNDF doesn't start failing and refetching until the router has been
up for an hour.
To improve integration even more, we fetch the floodfills first.
Ideally this should complete within the first half-hour of uptime.