Keep inventoty empty option

A simple QoL improvement for inventory management. Add an option for all blocks having inventory to keep it empty. Existing items will be sent to some other available places (if able) and no more new items can be stored in it untill "keep empty" toggle is on.

While being that simple, it solves a tons of problems when managing inventories. For example, you can finally stop filling all those connectors with items, I would argue to make connectors having "keep empty" toggle on by default. I often build small cargo containers to use them as access points in different places on base or big ships so I can have components available for welding or dumping staff back to the system, but they often become filled with random items, while I can remove them from being listed in inevntories, they can "hide" later some impotant items. So it wiuld be nice to have them empty all the time. You can also temporarily set "keep empty of many containers to make items quickly flow to a handful of target containers and then toggle the option back off, or even better, automate with events and timer blocks.

I am aware that sorters exist, but they usually add more problems to inventory management that solves. They are always unidirectional (no toggle to just disactivate them to allow backflow), and they are really in your way to be able to withdraw/deposit anything from any point of the system.