LP#1308590: Fix schema.org type mapping

The switch to config.coded_value_map for format icon types and labels
inadvertently broke schema.org type mapping. Restore it and attempt
to take advantage of the finer-grained types that are now available
to us.

Signed-off-by: Dan Scott <dscott@laurentian.ca>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>