feature: road-warrior clients resolve the domains of the new setting p2s.dns_domains with the router's resolver.

debian-package/src/usr/share/vpn-router/templates/road-warrior.conf.j2

@@ -39,5 +39,9 @@ pools {
   rw-pool {
     addrs = {{ p2s_address_pool }}
     dns   = {{ p2s_dns }}
+{%- if p2s_dns_domains %}
+    # INTERNAL_DNS_DOMAIN (RFC 8598): the domains the clients resolve with the DNS servers above.
+    25    = {{ p2s_dns_domains | join(', ') }}
+{%- endif %}
   }
 }