There are suspicions that the straight 5s retry could have caused a
situation a few days ago for `osu-server-spectator` wherein it was
getting hammered by constant retry requests. This should make that
a little less likely to happen.
Numbers chosen are arbitrary, but mostly follow stable's bancho retry
intervals because why not. Stable also skips the exponential backoff in
case of errors it considers transient, but I decided not to bother for
now.
Starts off from 3 seconds, then ramps up to up to 2 minutes. Added
stagger factor is 25% of duration, either direction. The stagger factor
helps given that if spectator server is dead, each client has three
separate connections to it which it will retry on (one to each hub).