add overall_wan_state on non-firerouter-managed platforms
add overall_wan_state on non-firerouter-managed platforms

firewalla/firewalla,MelvinTo/firewalla,firewalla/firewalla,MelvinTo/firewalla,MelvinTo/firewalla,firewalla/firewalla,firewalla/firewalla,MelvinTo/firewalla,MelvinTo/firewalla,firewalla/firewalla