Build Version Anzeige, WiFi auto off, redirect to Settings Site

lib/webinterface/webinterface.h

@@ -13,6 +13,7 @@ struct TelemetrySettings
   unsigned int active_time_seconds;
 };
 
+String firmware_version_string(void);
 bool webinterface_begin(TelemetrySettings &settings);
 void webinterface_handle(void);
 const TelemetrySettings &webinterface_settings(void);