Create the intelligent job dispatcher submodule

• "have a list of answers for each relay, and have an algorithm to choose which relay to test next, based on how many answers you have about it / what they were / when the oldest one was"

• "so when new relays appear, they get tested quite soon rather than waiting until their turn arrives"

• Skip adding a new batch of jobs if there are already 1.5xbatch_size jobs waiting in the queue.

• Add priority for URLs and methods