boomerang blade

Initial release

- Added the Boomerang Blade in six tiers: wooden, stone, iron, golden, diamond and netherite.
- Charge it like a bow and throw it in a straight line up to 8 blocks.
- It pierces several enemies per throw (1 for wood and stone, 4 for iron, gold and diamond, 6 for netherite).
- It flies back to the same inventory slot, or to another free slot, or drops at your feet.
- Each blade has its own damage and knockback, and loses 1 durability per enemy hit.
- Supports Sharpness, Knockback, Fire Aspect, Looting, Unbreaking, Mending and Quick Charge.
- Added the Walk enchantment: no slowdown while charging.
- Added the Battle Flow enchantment: after a hit, the blade jumps to the nearest hostile mob.
- Walk and Battle Flow have their own enchanted books and can be found at the enchanting table.