convert ItemType to scoped enum

and drop unused LRANGE enumerator

Change-Id: Id79e40ba1215eab770e8254fef280261cd36bfdf
Reviewed-on: https://gerrit.libreoffice.org/34202Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>