Add ability to increase truck import priority for ship repair buffer

Issue description

I set my shipyard to upgrade my main ship with lvl 1 cannons and armor, and despite good logistics, surplus, accessible containers, and idle trucks, none of the upgrade materials are being delivered to the shipyard.

I think this is a bug. It would also be nice to have conveyor inputs to the shipyard and vehicle depots.

Reproduction steps

This has been a persistent issue since the start of my save.

Game version and build number

v0.7.7 b470

Operating system

Windows

Attachments

github doesnt allow .save files so i saved it as .txt

save.file.save

You have storages with iron and mechanical parts with a "keep full" status, so the shipyard doesn't get anything.

Thank you for the help. Messing around with the "keep full" and "keep empty" settings for the relevant storages solved the issue, and trucks started delivering materials.

However, this only happened once I set my iron storage to "keep empty", which I find odd. I think that for something like the shipyard or vehicle depots, the trucks should automatically pull materials from neutral storages, even with no "keep empty" order.

For some reason, the developers didn't add a priority for the shipyard.