[SYS] Add save option to discovery and ohdiscovery key and remove discovery for Arduino boards (#1696)

Enabling to keep discovery off if required

Remove Mqtt discovery for Arduino UNO and ATMEGA

main/ZgatewayRF.ino

@@ -164,7 +164,7 @@ void RFtoMQTT() {
 
     if (!isAduplicateSignal(MQTTvalue) && MQTTvalue != 0) { // conditions to avoid duplications of RF -->MQTT
 #  if defined(ZmqttDiscovery) && !defined(RF_DISABLE_TRANSMIT) && defined(RFmqttDiscovery) //component creation for HA
-      if (disc)
+      if (SYSConfig.discovery)
         RFtoMQTTdiscovery(MQTTvalue);
 #  endif
       pub(subjectRFtoMQTT, RFdata);