Stop using generic_54.png

Currently generic_54.png is the one and only texture used for the GUI of chest, double chest, ender chest, trapped chest, barrel, chest in minecart, and chest in boat. This make creating a texture pack with custom GUI for each of the GUI mentioned above impossible. Since all of the other container GUI in the game uses their own texture anyways, I think moving on from generic_54.png will make texture pack more versatile.