DLG_MAILMERGEWIZARD conversion to .ui

Conflicts:
	sw/inc/dbui.hrc

Change-Id: Id224fd3a99abe8ec497a38c40b099dd7ae917890
Reviewed-on: https://gerrit.libreoffice.org/10494
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>