Reduce despawn timer on Voidwatch chests

[Primus]

It would fix all problems with AFK'ers and trolls if Voidwatch chests had a really short despawn time, something like 15-30 sec.

[Khiril]

Id settle for a "name has not received their treasure" message. But yes, all the yes. VW box is HARDER to kill than the Mobs are, since day 1.