Aerobatic Elytra

Added a cosmetic ability for elytras named Rocketless that can hide the rockets from the elytra model for cosmetic purposes.

• Added bundled datapack which adds an upgrade recipe using paper that toggles the Rocketless ability
• Changed upgrade recipes so they don't consume more items when that'd result in the original state (so toggle upgrades only suck one item)
• Added an item property named aerobaticelytra:hide_rockets to alter the item model based on the Rocketless ability