Add of SONOFF RFR3 environment

Relay ok
Button press ok
RF reception 433toMQTT ok
To have the RF reception you need to connect D0 of SYN470 to GPIO4 of ESP8285. Instruction to follow. Do not do that if you are not confortable with soldering and don't have an electrical background.

main/config_GPIOInput.h

@@ -34,10 +34,12 @@ extern void GPIOInputtoMQTT();
 #define GPIOInputDebounceDelay 60 //debounce time, increase if there are issues
 
 /*-------------------PIN DEFINITIONS----------------------*/
-#if defined(ESP8266) || defined(ESP32)
-  #define GPIOInput_PIN 14
-#else
-  #define GPIOInput_PIN 7
+#ifndef GPIOInput_PIN
+  #if defined(ESP8266) || defined(ESP32)
+    #define GPIOInput_PIN 14
+  #else
+    #define GPIOInput_PIN 7
+  #endif
 #endif
 
-#endif
+#endif