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

ZsensorGPIOInput.ino

@@ -71,6 +71,7 @@ void MeasureGPIOInput(){
       if (InputState == LOW) {
         trc(F("GPIO LOW"));
         GPIOdata.set("gpio","LOW");
+        pub(subjectGPIOInputtoMQTT,"LOW");
       }
       if(GPIOdata.size()>0) pub(subjectGPIOInputtoMQTT,GPIOdata);
     }