fdo#81475 reorganization of writer's table toolbar

Change-Id: I3672fa8e32975723d58e92fe3eceafc2e8993646
Reviewed-on: https://gerrit.libreoffice.org/13267
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>