Add Draco Compression to mbgrd2gltf

Monterey Bay Aquarium Research Institute (MBARI) is an organization dedicated to better understand marine life and the ocean. One of the ways they do that is by visualizing the seafloor through 3D graphics with the help of STOQS. Their current approach of building GLTF files results in very large files. Our goal is to incorporate the Draco library by Google in the current process to reduce the resulting file size.