Arduino OTA enabled on MQTT Gateway

MQTT gateway example implements OTA update using Arduino mechanism. Now a gateway that uses that firmware (both ESP8266 and ESP32) is shown in Arduino IDE as a OTA enabled sink. Notice that network password will be used for OTA too.

Bugfix: Control commands code mismatch fixed
Bugfix: Control commands were treated as CayenneLPP by mistake
Bugfix: Fixed Arduino.h case for Linux machines
New feature: Nodes resend last data message after an invalidate message if reason is not key expired
New feature: Arduino OTA implemented on MQTT gateway example