Kea DDNS can not listen on 0.0.0.0

Kea DDNS can not listen on 0.0.0.0. This is a problem if using DDNS in hostname-based environment with unknown IP like docker networks.

DHCP_DDNS_CONFIG_FAIL DHCP-DDNS server configuration failed: IP address cannot be "0.0.0.0" (/etc/kea/kea-dhcp-ddns.conf:3:23)
DCTL_CONFIG_FILE_LOAD_FAIL DhcpDdns reason: IP address cannot be "0.0.0.0" (/etc/kea/kea-dhcp-ddns.conf:3:23)
Service failed: Could Not load configuration file: IP address cannot be "0.0.0.0" (/etc/kea/kea-dhcp-ddns.conf:3:23)

I think it should present a Warning message like setting IP defined one other than 127.0.0.1 and not an error preventing starting up a service.

Check is performed in src/lib/d2srv/d2_config.cc

void
D2Params::validateContents() {
    if ((ip_address_.toText() == "0.0.0.0") || (ip_address_.toText() == "::")) {
        isc_throw(D2CfgError,
                  "D2Params: IP address cannot be \"" << ip_address_ << "\"");
    }