Updated GUI

Updated GUI now uses OptiGUI. While not required, it’s recommended to use it so each storage container can have its own unique interface.

Multiple alternative generic_54 textures are included if needed. The generic_54 texture labeled “Storage” can be applied to chests, ender chests, and barrels when OptiGUI is not installed. Additionally, unlabeled generic_54 options are there for server use to prevent interference with plugin-named chests as this resource pack is experimental.