Mqtt discovery (#320)

* add mqtt discovery (compatibile with home assistant) with omg status binary sensor & bme280 sensor

* added mqtt discovery to Test_config.h for ESP32 (ESP8266 & other boards was not tested)

* include support for ESP8266 & arduino mega

* fix getting MAC for esp8266

* esp8266 fix

* make mqtt discovery functions functions more generic, readable and easy to use & extend

* make mqtt discovery functions functions more generic, readable and easy to use & extend PART 2

* remove the macro for each attribute and supposing that if there is a bme280 we expose all

tests/Test_config.h

@@ -129,6 +129,7 @@ const byte subnet[] = { 255, 255, 255, 0 }; //ip adress
   #define ZgatewayRFM69 "RFM69"// If you uncomment this you can't use RF and BT due to the fact that RF use also D8 and BT use also D6/D7
   #define ZsensorGPIOInput "GPIOInput"
   #define ZsensorGPIOKeyCode "GPIOKeyCode"
+  #define ZmqttDiscovery "HADiscovery"//ESP8266, Arduino, EPS32, Sonoff RF Bridge
   #define jsonPublishing true
   #define simplePublishing true
 #elif ESP32
@@ -149,6 +150,7 @@ const byte subnet[] = { 255, 255, 255, 0 }; //ip adress
   #define ZgatewayRFM69 "RFM69"
   #define ZsensorGPIOInput "GPIOInput"
   #define ZsensorGPIOKeyCode "GPIOKeyCode"
+  #define ZmqttDiscovery "HADiscovery"//ESP8266, Arduino, EPS32, Sonoff RF Bridge
   #define jsonPublishing true
   #define simplePublishing true
 #elif defined(__AVR_ATmega1280__)
@@ -171,6 +173,7 @@ const byte subnet[] = { 255, 255, 255, 0 }; //ip adress
   #define ZgatewayRFM69 "RFM69"// If you uncomment this you can't use RF and BT due to the fact that RF use also D8 and BT use also D6/D7
   #define ZsensorGPIOInput "GPIOInput"
   #define ZsensorGPIOKeyCode "GPIOKeyCode"
+  #define ZmqttDiscovery "HADiscovery"//ESP8266, Arduino, EPS32, Sonoff RF Bridge
   #define jsonPublishing true
   #define simplePublishing true
 #else // for arduino Uno