Berry virtual Alexa Hue device

[s-hadinger]

Description:

Introduce virtual Alexa Hue devices. I.e. you can now create virtual lights in Berry and receive commands from Alexa (without actual lights or GPIOs).
Documentation will follow.

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with Tasmota core ESP32 V.2.0.2.1
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass