There are a number of ways to solve this.
Ports could request bots from the network, the source could either be docked bots in other ports or bots sitting in the inventories of chests. Here is a mockup:
This would cause 10 construction bots to bring themselves to dock with the port or logistic bots would bring 10 from any chest inventories they find. This would mean you could also order them directly to the player inventory as you normally would with other things. The logistic system could also see the ports as chest inventories. I imagine this would be easier to implement as you don't have to program the construction bots to fly themselves to fulfil an order, the logistic bots would just grab them from the ports. Then you don't even need to have the ports request orders, you can.
A workaround I found was to place some things and a storage chest close to a roboport and issue a deconstruction plan on them, bring the construction bots to that area so that they would dock with that specific port when they were done. Then you can just collect them.
