08. ESP32 Logging

See

• https://thingpulse.com/esp32-logging/
• https://www.mischianti.org/2020/09/20/esp32-manage-multiple-serial-and-logging-for-debugging-3/

(With workaround for ESP8266; see https://github.com/matthias-bs/BresserWeatherSensorReceiver/blob/e00def438ea19b6ae5d7069752e4f8cde8ab6f72/src/WeatherSensorCfg.h#L464)