Add the ability to link out to sameAs entities

Add the ability to link out to sameAs entities

Look for standard identifiers with known URIs, such as
LCCNs, OCLC numbers, and URIs identified in 024 fields,
and add http://schema.org/sameAs properties to the record.
This helps us link out to the broader linked data world,
and should help those consuming our data to better
understand what resources we have to offer.

Signed-off-by: Dan Scott <dscott@laurentian.ca>