Extend PHASE_IDLE_TIMEOUT from 10 seconds to 30 seconds

Extend PHASE_IDLE_TIMEOUT from 10 seconds to 30 seconds

The 10 second value was always known to be aggressively short. I had
this in there with such a short value because we didn't have the
feature to auto-advance a phase after every single player was in, nor
to auto-idle the phase after the players-waiting list is emptied. So
without those features implemented, players were forced to wait for
the idle timeout in situations where there was nothing to wait for. So
to keep that from being too annoying, I had this parameter dialed
down.

But now that those two missing features were implemented in recent
commits, we take this timeout up to a higher value. With this,
hopefully the Move On button won't appear too soon so that people
inadvertently skip an active player, but instead only appears once
people really are stuck waiting.