SLAAC WAN: add support for requesting DNS info via stateless DHCPv6 (#5937)
SLAAC WAN: add support for requesting DNS info via stateless DHCPv6 (#5937)

* Merge SLAAC interface dhcp6c config

Stateless DHCPv6 config for SLAAC WANs was generated, but not merged into dhcp6c.conf file.

* Add support for stateless DHCPv6 to dhcp6c script

Script had no code for processing stateless DHCPv6 replies (required for SLAAC without RDNSS / DNSSL).

* dhcp6c script, pass all search domains to ifctl

Only the first domain was used, all others were disregarded.
opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core