Different timeouts/minimum speeds for upload vs download

[matyasselmeci]

Aborting an input transfer because the transfer is too slow is usually not that big of a deal because you won't have lost much time at that point during the job. However, if you abort an output transfer, you'll have lost all the time spent generating the output (which could be several hours). Therefore, timeouts and minimum transfer speeds for write-back should be much more forgiving than for downloads. Maybe add a random-wait-and-retry feature (though that could be a separate issue).