Document how to Add DAC Replicas to Helm/YAML Deployments

https://docs.couchbase.com/operator/current/concept-operator.html

On this page we indicate that it is possible to create replicas of the DAC:

The DAC is stateless so more than one replica may be run for high-availability.

However at no point do we mention how to do this, either for a Helm deployment nor if using the cbopcfg tool.

Would it be possible to add how this can be achieved to the necessary points of our documentation?