Added a postgresql data import script

[EvanCarroll]

Not sure if you want to provide data-import scripts, but this one will work for PostgreSQL for those that want to use the database.

[ClevelandArtGIT]

Hi Evan. Generally speaking, since this repo is just data, we don't accept pull requests. That said, we appreciate your interest and efforts and are looking for the best way to incorporate your scripts into our initiate. Thanks.

Ethan Cleveland Museum of Art