Cheaper Lantern Recipes

My very first datapack was a recipe for (only) iron lanterns, with 4 nuggets instead of 8. Now I'm revisiting this idea and adding it to copper as well! I also removed the vanilla recipe and added a recipe granting advancement, so you will have the exact same experience as with vanilla, only cheaper. There's no risc of using 8 nuggets. (I forgot soul tho, that's why this is beta.)