* 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
* Add initial support for USB MSC
* Add Firmware Upload/Download With MSC
Current running firmware is available as file inside the MSC Disk. To update the firmware on the ESP, just copy a regular firmware bin into the drive
* Support overwriting of the firmware file
Overwriting a file is done totally differently on MacOS, Windows and Linux. This change supports it on all of them.
* Allow CDC, FirmwareMSC and DFU to be enabled on boot
* Add example ESP32-S2 USB-ONLY board
* Various device code optimizations
Added `end()` methods to MSC classes
Made begin() methods safe to be called multiple times
Optimized CDC class
* Fix CDC Connect/Disconnect detection in Arduino IDE on Windows
* Rework cdc_write
* Update ESP32-S2 board configs
