Wandering Trader rework

Make Wandering traders appear with a 'trading stand" that will last for 3 days. Wandering traders will have tiered trades (2 trades per tier). Traders will despawn with the stand. Traders can come in 16 robe colors, and one of the Overworld wood types. Some dye robes can come with the wood type, like a brown robe with Jungle wood, or a red robe with Oak, Birch, or Spruce wood. For the tiers, rare items will have higher tiers and in those tiers will have "sub-tiers", where different items will be rarer than others. Traders can trade almost everything, besides Bedrock, elytras, etc. Higher trades will have higher prices, more than emeralds.