... text:illustration-index-entry-template, so store these elements
only in ODF 1.2 extended, and in loext namespace.

Change-Id: Icf919e91114f5c9aed2adc3f5359b9df61eb3433
Reviewed-on: https://gerrit.libreoffice.org/46088Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>
(cherry picked from commit a26c4448)
Reviewed-on: https://gerrit.libreoffice.org/46109Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>