Explore having a supplementary STAC side of the catalog

[phargogh]

Lisa came across STAC at a NASA-organized open science session at AGU, and I think this would be a really great thing to be able to include as a feature of our CKAN catalog.

There appears to be an open discussion in CKAN's repo about supporting STAC atop CKAN's existing functionality, so until that's implemented and available, whether in vanilla CKAN or as a plugin, it would be neat to explore if there are any ways to implement our own STAC index outside of CKAN.

I think a very reasonable constraint here is that this would only be for our public data.

If needed, we could further constrain it to just our global layers or something like that.