Implement a new function or API endpoint that allows libraries to easily retrieve the structured data (metadata, ID/ISBN, image URL, link) for any active "Showcase". The data should be presented in a standard, machine-readable format like JSON or XML.

While Vega Discover allows us to embed the visual display of a Showcase on other websites, this does not give us the underlying data. This data could be used to include Showcases i mobile apps and integrate with other systems and external analytics tools. They could also be used by patrons to easily keep track of new additions to "permanent" showcases.