Better Traders [Datapack]

-Added an expensive trade to buy wet sponges as an option for the final trade slot

-Added a trade to buy scutes for 5 emeralds

-The fern trade now gives 3 ferms but only has 8 max uses

-The red sand trade is now more common in relation to the sand trade

-The explorer map trade is more common

-Added a pack.png and updated the description of the pack. This is mostly to allow it to look nice on the datapack selection screen during world creation..