Ice Break Damage Attribute

[TheDeathlyCow]

Adds an attribute that controls damage dealt when shattering the ice of a rooted opponent. By default the damage is 3, but the Ice Breaker enchantment will increase it by 1 per level.

TODO:

• Config for the base value. May be too early for the entity default value, but should be ok for a fallback if no entity attacks the victim
• Balance test a frostologer fight - this is a LOT of damage!!