It would be nice if you could add some kind of workers that can transport items e.g. from a quarry to a chest

There is -- see the Courier NPC type. He is an NPC dedicated to moving items from one place to another, via a configurable route and items list. Look in the instruction manual for more information.

so sorry just discovered that. but thanks anyway

No worries -- there is a ton of stuff in the mod, easy to overlook something.