Space platform item maximum should respect chosen planet

[Gergely]

What?

Make it so that space platform maximum item requests only drop the surplus items onto the planet specified in the "import from" box. In other words, the entirety of the filter, both the minimum and maximum should only be active while the platform is over that planet.

Why?

Currently if I set a maximum for an item request on a space platform, no matter what planet is chosen for the item, the surplus will be dropped onto any planet. It is unreasonable to expect that all planets on the platform's route are equipped to deal with the items. Because of this, it is never beneficial to use the maximum setting, except in weird scenarios where the hub is involved with on-platform logistics (asteroid processing, ammo and fuel manufacturing) which is not it's intended use anyway. I propose a change that could make the maximum setting useful in more cases.

Use case

A use case for planet-specific maximum filter is depositing unwanted items to the planet's surface logistic network. I could set up my landing pad to also request a maximum of zero of the items, and they are taken by the logistic bots to storage from the landing pad's trash slots. Semantically, I am getting rid of unwanted items from the platform, instead of wanting them on the surface. Sort of like an active provider chest.

[ncc1702]

This would help with pushing items surface side instead of always pulling them
And would mimic the "cargo empty" feature of trains

[AIdrick]

An other use case:
I got ships that collect stuff from the inner planets and deliver them to Aquilo. On Nauvis they get refueled with uranium fuel cells.
They should also drop the empty cells only on Nauvis. At the moment i have to set the "Unload" checkbox for Nauvis so the cargo landing pad can request them from the platform. Unfortunately it then also requests other stuff meant for Aquilo.