ViewDocument3 method takes OpenType parameter, which allows to decide
if user can choose opening the document read-only or to edit.

This backport of commit f60cc89e does
not include l10n stuff and dedicated helper executable, using dialog
resource strings.

Change-Id: I0ad53ba64272fb84728d2221e3dc85d3eefdda68
Reviewed-on: https://gerrit.libreoffice.org/72355Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/72518