Default to listening on ::

Currently following is required to make Dragonfly operator work IPv6 only or dual stacked environments:

  args:
    - "--bind=::"
    - "--admin_bind=::"

As the day of CONFIG_IPV4=n is getting closer by every day I would suggest switching listening from 0.0.0.0 to :: in Dragonfly binary itself

This is compatible with all modes IPv4-only, IPv6-only and dual stack