Apparently we were already getting this info because it's a unit like
any other according to the event system, so if runways were actually
sufficiently damaged we'd emit a ton of exceptions.
This doesn't do anything yet, but tracks the damage state. Will add the
ability to repair them next, and then finally make the damage render the
runway inoperable.
The aircraft that have not been fragged will now be spawned in parking
to provide more targets for OCA strikes. We do this only at airports,
not carriers. The AI has enough trouble taxiing around uncrowded carrier
decks that we probably shouldn't make it harder for them, plus most of
the aircraft will be stored below the flight deck (we allow 90 aircraft
to be stored at the carrier, which certainly will not fit on the flight
deck).
The aircraft are spawned in an uncontrolled state and nothing will
activate them, so aside from the cost of rendering them they shouldn't
affect performance.
Fixes https://github.com/Khopa/dcs_liberation/issues/148
Generated units are added to this during mission generation so we can
map destroyed units back to the data that generated them. Currently only
implemented for aircraft as a proof of concept.
