[Sea of Claws] Vehicle traits

[Forien]

Sea of Claws expands Vehicles, so they can not only have Upgrades (vehicle modifications), but also Traits.
Distinction is that traits are decided upon Ship's creation, while Upgrades, like all other modifications can be added at will later.

It probably makes most sense to use existing trait type Item, however Vehicle Sheet needs space to display them.

Perhaps add dropdown to traits, so they can be selected to have subtype, as being "creature" or "vehicle" traits (similar to trapping subtypes)