More Gems [FABRIC]

I'm adding a config option for treasurebag skyblock. It does the following:

• changes the treasure bag data json to use treasure_bag_skyblock.json, which contains the normal treasure bag drops plus adds the jujus and the 10 gems as posibble drops. This JSON can be adjusted by players with a datapack to put any valid item in the game, including other mods.
• adds a wandering trader entry for treasure bag at the cost of 1 iron ingot and 1 emerald
• adds an event check when the player kills an entity to give a chance for the entity to drop a treasure bag on death
• adds a config entry to set the chance of a killed entity to drop a treasure bag, default is 0.25 or 25% chance