Add support for ESP-NOW

[mores]

Is your feature request related to a problem? Please describe.
The problem is that there is no Wifi where I would like to control pixels.

Describe the solution you'd like
I would like to control pixels WITHOUT the need to connect to a WiFi network.
This can be achieved using the ESP-NOW functionality built into the ESP32

Additional context
https://www.espressif.com/en/solutions/low-power-solutions/esp-now
https://docs.espressif.com/projects/arduino-esp32/en/latest/api/espnow.html#:~:text=ESP%2DNOW-,About,sending%20and%20receiving%20data%20packets.

[MartinMueller2003]

Does this library integrate into the IP stack? Very much would not want to implement an alternative data path. FYI: The WiFi specification support a sta-to-sta mode. Not sure if the ESP implementation supports that part of the spec.

[mores]

The Arduino docs have some good information: https://docs.arduino.cc/tutorials/nano-esp32/esp-now/

ESP-NOW operates primarily at the data-link layer of the OSI model