Frozen Zombies

Adds the Frozen Zombie mob from Minecraft Dungeons. These zombies spawn in biomes defined by the #wich:spawns_frozen_zombies tag [default minecraft:ice_spikes and minecraft:snowy_plains]. When killed by a player, they have a chance to drop a snowball. Zombies trapped in powdered snow can convert into Frozen Zombies the same way skeletons convert into strays. Frozen Zombies submerged fully in water can melt back into zombies. Frozen zombies chase players around, throwing snowballs and applying a slowing effect on hit and attempting to melee attack slowed targets.