Dual-Stack for bmcd

[grisu48]

With bmcd version 2.0.5 it is only possible to connect via IPv4 to the BMC WebUI. It would be great to have bmcd listening on both, IPv4 and IPv6.

Describe the solution you'd like

By default, making bmcd listen on all interfaces and all addresses, both IPv4 and IPv6.

Describe alternatives you've considered
I've tried adding host: "::" to /etc/bmcd/config.yaml and also host: "<IPv6>" but neither seemed to work. Either case, this would make bmcd listen only on IPv6, which is also not the desired goal.

Additional context
None