Add Quantity Roll field to more item types

[HigginsTheRed]

Could the "Quantity Roll" field on the Ammo item type be added to other item types? Currently when using scavenge actors only ammo can produce more than one of an item for a single table roll. Explosives, Thrown Weapons, and Bobby Pins all have variable quantities in the Core Rulebook loot tables.

[QckSilverDragon]

Similar to issue #253