Custom firmware for CRM3007L

This project is published when there's plenty is done already so let's describe what's already working.

• OnBright MCU specific HAL is extracted and adapted for SDCC
• The code compiles and runs on the actual MCU

What's next:

• Make OTA library for ESP32 to be able to flash OnBright MCU without proprietary flasher
• Make WDT work with ADC (right now ADC fails when WDT is enabled)