Description of problem:
Attempting to deploy designate mdns with an ipv6 external network does not work because the service is configured to listen on 0.0.0.0:5354 (default) instead of [::]:5354.  Looking at the tripleo heat templates, there is no option to configure the listener, but the underlying puppet module for designate mdns supports it.

Attemping to create a zone with mdns listening on 0.0.0.0:5354 results in an eventual ERROR status.

As a workaround, the listener settings can be set using ExtraConfig-style parameters:
  ControllerExtraConfig:
      designate::mdns::listen: '[::]:5354'

Version-Release number of selected component (if applicable):
OSP 16.1
python3-tripleoclient-12.3.2-0.20200615103427.6f877f6.el8ost.noarch

Steps to Reproduce:
1. Deploy OSP 16.1 with an ipv6 external network
2. Deploy OSP 16.1 with designate-config-ha.yaml
3. Attempt to create zones

Actual results:
Zone will start off in PENDING and eventually transition to ERROR.
refresh: retry limit for master ... exceeded messages will show up in logs for designate_backend_bind9

Expected results:
Successful creation of zone.