Admins can export GeoSpatial records as Aardvark JSON files

[spilth]

In order to remain backwards compatible with GeoBlacklight and the communities that use our data, we need to provide an Aardvark JSON export format for our GeoSpatial records.

We will need a custom template to provide this export in order to glue our GeoServer URL config variables into the JSON.

Note: We might need/want a way to differentiate geospatial records from non-geospatial records and NOT provide Aardvark JSON files if it's not geospatial data.

This will require final decisions on metadata.