Mqtt discovery for ha (#323)

* MQTT discovery factoring

* add DHT discovery

* BME topic macro change

* add sensors to ha discovery

* correct a comment typo #327

* let the possibility at buildtime to don't publish service data

* reduce string usage

* change MQTT ONOFF actuator to ON OFF commands instead of true false

* add ZactuatorONOFF discovery

* add simple publishing for GPIO input

* Add RF switch and gateway discovery

ZgatewayRF315.ino

@@ -136,9 +136,7 @@ boolean RF315toMQTT(){
 #ifdef jsonPublishing
   void MQTTtoRF315(char * topicOri, JsonObject& RF315data) { // json object decoding
   
-    String topic = topicOri;
-  
-    if (topic == subjectMQTTtoRF315) {
+   if (strcmp(topicOri,subjectMQTTtoRF315) == 0){
       trc(F("MQTTtoRF315 json data analysis"));
       unsigned long data = RF315data["value"];
       if (data != 0) {