DLG_INDEXDESIGN conversion to .ui

Change-Id: I84d6531a73e6e726359bd20664b6299ad8a390ee
Reviewed-on: https://gerrit.libreoffice.org/9699
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>