Enable to set the WM pwd from the Mac (#1323)

So as to reinforce security for AP configuration access, enable to set the Wifi Manager Password from the 8 first digits of the ESP Mac address

platformio.ini

@@ -291,6 +291,7 @@ build_flags =
   '-DZsensorGPIOKeyCode="GPIOKeyCode"'
   '-DZgatewayWeatherStation="WeatherStation"'
   '-DsimplePublishing=true'
+  '-DWM_PWD_FROM_MAC=true'
   '-DGateway_Name="OpenMQTTGateway_ESP32_ALL"'
 
 [env:esp32dev-rf]