Add Office::Histories::HistoryItem::ReadOnly flag to configuration so
that a document that was opened read-only isn't opened as editable from
recent documents.
Change-Id: I6985da287d3337a53a7e41e8e500421038eedb91
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/133385
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
