Mending rebalance

Mending will come in 3 levels instead of just 1. XP orbs will no longer repair durability. -Gear enchanted with Mending no longer receives a work penalty on the anvil. This will reduce the cost of subsequent enchantments added to that gear and eliminate the risk of it becoming "too expensive" to repair or enchant. -For each level of mending, Repair materials restore 25% more durability. At level 3,a single diamond would fully repair any diamond gear. -Combining gear grants an additional 10% durability bonus per level. Also, using end raided gear to repair your gear is viable since anvil cost wouldn't increase with each use.