Add metadata for cscl pub file geodatabase

[mattyschell]

We plan to add the published version of CSCL to NYCmaps as a zipped file geodatabase. Add a single "published cscl file geodatabase" entry to the metadata.

That entry should link to a page that describes the published cscl geodatabase in full. List all layers in the geodatabase. Where metadata entries already exist for these layers create links.