New Route Assignments and Dumping

Describe the issue
Storage will not dump unless "keep empty" is on.

If you link a mining tower to import a dumpable material to a storage (which you want general trucks to dump), you receive an error if you try to keep it empty.

Solution - Must still use the two storage trick as dumping has no "keep full" ability to request from the storage.

Expected behavior
Well it's as expected based on the new changes, but wanted to report a unique situation giving some trouble in the discord. Perhaps a toggle on the storage to indicate its for "Dumping"? Or a global setting/priority to say pull from storage for dumping.

To Reproduce
Steps to reproduce the behavior:

1. Link mine tower to storage.
2. Try to dump that storage.

Additional context

• Game version: 0.4.5a

Having routes ignore sliders was already mentioned by several players but that change is currently a bit bigger and risky so not happening soon.

A more feasible workaround might be, if a storage containing dump-able material is linked to a mining tower with dumping. Go ahead and treat the dump area as "keep full" storage so it pulls out from the storage.

I think areas designated for dumping, should be treated as storage units that need to be filled. I should never have to micro-manage the game by constantly adjusting sliders and/or turning outputs of storage units on and off. Just to get the trucks to dump all the thousands of units of dirt or rocks that I have stored.
There should be a toggle on the storage, or the mine/dump tower to force the issue, and a matching priority setting that may be adjusted.