bundles/wide-dhcp6c: introduce, add to home.router

bundles/wide-dhcp6c/files/ip-down

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+systemctl stop wide-dhcpv6-client
+
+% for interface, subnet_id in sorted(targets.items()):
+for IP in $(ip -6 addr show dev ${interface} | grep inet6 | awk '{print $2}' | grep -vF 'fe80::')
+do
+    ip -6 addr del $IP dev ${interface}
+done
+% endfor