Better Airdrop Production

This change allows the Production class and its children to take in multiple actors to be produced.
This is needed for #7055 so that the units produced can exit in an orderly fashion.
That would require unneccesary variables inside the class, since this method is using a lot of the stuff that is in this method, and I cant add parameters to it since the CallFunc activity cant pass any.

Most of the variables above like exitLocation etc would need to be stored in the class instance and I would rather not do that unless there is an overwhelming majority for it.