Table import: Set GPU Instancing flag and shared material

For hybrid renderer instancing, duplicate meshes more or less need to share the same material. Some values can be overridden on a per instances basis. The GPU instancing flag also needs to be set. This should probably be set by default, though it may come with overhead that im not aware of when set for materials that will not actually be used in instancing so it may be best to pair it with meshes that we know are shared.