PURL setup for classes in new API

The old setup relied on a /virtual/ONT_ID/SHORT_ID schema that doesn’t
exist for /ontologies/ONT_ACRONYM. This commit adds it, so
/ontologies/ONT_ACRONYM/CLASS_ID now works.
Look for referrer and if it's PURL then redirect to classes
Temp debug statement
Remove referrer data
Don't override conceptid when it exists for PURLs
Add route for PURL server to use