Support multiple comma separated values with OR for `type=` param

See https://github.com/lobid/lodmill/issues/508

Deployed to staging, see:
http://test.lobid.org/subject?name=Heinsberg&type=http://d-nb.info/standards/elementset/gnd%23BuildingOrMemorial,http://d-nb.info/standards/elementset/gnd%23PlaceOrGeographicName&format=full