Add flag disable-item-use to select usable items

### The Problem

It would be great if WorldGuard had a `disable-item-use` flag.
This flag could be set with strings like the `deny-spawn` flag for example, but with items that can be used.
Some examples for these items would be the Elytra or some Food Items like Golden Apples or the Milk Bucket.

### A Solution

/\

### Alternatives

I don't really see an alternative...I didn't find any other flag that could somehow do this

### Anything Else?

I guess not :)