Increase brightness and generate unique MQTT client ID

Release 2.0.2 brings the following new features and improvements for ANAVI Light Controller:

• Generate unique MQTT client ID based on the machine ID.
• Increase brightness by setting PWM range 0 to 255. According to the documentation the default range in Arduino core for ESP8266 is up to 1023: https://arduino-esp8266.readthedocs.io/en/latest/reference.html#analog-output

Thanks to @hackman for suggesting both improvements!