Add Dublin Core metadata scraping
Add Dublin Core metadata scraping

Also, scrapeAllMerged now cancatenates values if they are arrays.

Bug: T76224

iSCInc/html-metadata,d00rman/html-metadata,wikimedia/html-metadata,martindale/html-metadata,wikimedia/html-metadata,d00rman/html-metadata,davemorro/html-metadata,GEOFBOT/html-metadata,martindale/html-metadata,iSCInc/html-metadata,GEOFBOT/html-metadata,davemorro/html-metadata