* Add two more dfrobot microcontroller board definitions

* remove duplicate definitions

* Initial implementation of RGB driver via digitalWrite

* Moved constants to pins_arduino.h

* Changed pin definition + added example

* Wrapped BlinkRGB in #ifdef BOARD_HAS_NEOPIXEL

* Removed forgotten log from example

* Moved RGBLedWrite to new file esp32-hal-rgb-led and created pinMode in variatn.cpp

* Updated example - lowered single channel brightness to LED_BRIGHTNESS

* Changed function name from RGBLedWrite to neopixelWrite + code polishing

* Moved pinSetup portion related to RGB back to common file

* GPIO refactoring

GPIO now using ESP-IDF API on all chips.
LEDC interrupt fix removed - no longer needed.
Edited pins_arduino.h in variants according to changes in gpio.

* Edited analog channels functions