Bug 10309: (follow-up) Updates for Bug 6594, Schema.org structured data

Bug 10309: (follow-up) Updates for Bug 6594, Schema.org structured data

This patch adds the changes from Bug 6594:

"To support schema.org processors, such as Google, Bing, and Yandex,
structure our data so that it has machine-readable attributes. This pass
declares the CreativeWork sub-types as well as Product for the main
bibliographic record details, and uses the Offer type for holdings
information per the W3C Schema Bib Extend community group discussions."

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Tested against linter.structured-data.org, microdata present
No errors.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>