Add a configurable delay between jobs in same Queue#425

THis can be a general setting for all Queue’s to begin with, I would be more then happy.

The idea is that if I have 10 printers in 1 Queue e.g. PLA_COLOR and no jobs, my printers are idle.

Then 10 print jobs are added to that queue causing all 10 printers to start simultaneous.
My printers have a 1000W print bed, causing 10k Watt to be used leading to issues :)

So if ther is a delay like 2 minutes, each printers would start 2 min after each other solving electrical overload within a queue.

This would be a god start.