DLG_MM_SENDMAILS conversion to .ui

Change-Id: I5611508e9024032e9213636be94410280618f9e5
Reviewed-on: https://gerrit.libreoffice.org/10459
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>