Add GS1 Web Vocabulary known value registry (codepoints 3000-3608)

Add 609 known values from the GS1 Web Vocabulary ontology covering
global supply chain and product identification concepts. Update the
known value assigner to support Turtle (.ttl) format and configure
the GS1 ontology source. Add GS1 entry to the known value
specification table and description section.

Author: wolfmcnally