More Ammo Mod

Adds three custom ammo types to the shop loot pool as Rare items (Cost: 30, Sell: 15):

Black Hole Ammo: Creates a temporary gravity well on impact that draws nearby targets in.
C4 Ammo: Attaches a sticky C4 device to hit targets. Shooting them a second time detonates the charge, destroying all targets in a large radius.
Splitter Ammo: Splits into two additional hitscan shots on target hit, dealing damage and drawing cyan visual tracers to the nearest targets.