Add Waveshare ESP32-S3-ETH-8DI-8RO board support

[jdavis-codes]

Checklist

• Please provide specific title of the PR describing the change
• Please provide related links
• If you are adding a new board, please make sure
  • Provide link to your allocated VID/PID if applicable
  • UF2_BOARD_ID in your board.h follows the correct format from the UF2 specification

Related links

• Product: https://www.waveshare.com/esp32-s3-eth-8di-8ro.htm
• USB PID allocation: Allocate PIDs 0x83A1-0x83A3 for Waveshare ESP32-S3-ETH-8DI-8RO (RS485 version) espressif/usb-pids#344

Description of change

Adds TinyUF2 support for the Waveshare ESP32-S3-ETH-8DI-8RO, the RS485 version of Waveshare's industrial eight-input/eight-relay controller.

I'm an individual not associated with Waveshare, but I own the board and have successfully built and flashed it. I hope to use it for teaching farm automation workshops, and try out CircuitPython in farming and industrial contexts.

Board configuration:

• ESP32-S3-WROOM-1U-N16R8
• 16 MB flash using DIO mode
• 8 MB octal PSRAM
• GPIO0 BOOT-button entry during the second-stage bootloader window
• WS2812 status NeoPixel on GPIO38 with GRB channel order
• Espressif VID/PID 0x303A:0x83A3
• UF2 board ID ESP32S3-ETH8DI8RO-v1.0
• UF2 volume label WSRELAYBOOT

PIN_DOUBLE_RESET_RC is intentionally not enabled because an RC-backed double-reset pin has not been verified on this board.

Validation

• Generated board metadata successfully with tools/gen_boards.py.
• Built the ESP32-S3 TinyUF2 image successfully using ESP-IDF v5.3.2.
• Verified the resolved build configuration uses the 16 MB partition table and DIO flash mode.
• onboard LED color mapping looks good.

[jdavis-codes]

I can squash the commits for cleanliness if that is desired.

[hathach]

look good, thank you