fff-wireguard: Add nodewatcher Script

With this script the monitoring have the correct information that the router is
connectet with wireguard or not.

Signed-off-by: Christian Dresel <freifunk@dresel.systems>

src/packages/fff/fff-wireguard/files/usr/lib/nodewatcher.d/15-wireguard.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Netmon Nodewatcher (C) 2010-2012 Freifunk Oldenburg
+# License; GPL v3
+
+# Checks if wireguard has peers
+vpn_active=0
+wg | grep hands >/dev/null && vpn_active=1
+SYSTEM_DATA="$SYSTEM_DATA<vpn_active>$vpn_active</vpn_active>"