pybricks
[Feature] Build HAT ADC and Battery drivers
The Raspberry Pi Build HAT has an ADC that monitors the voltage input. This can be connected to a mains supply or to a battery pack.
We need to implement an ADC driver to monitor this voltage and then set up an ADC battery driver instance so that users can get the battery voltage from hub.battery.
We need to be careful with the low battery shutdown though. The shutdown will be different than other hubs since there isn't actually any power control on the Build HAT. The only thing we could actually do is turn off as much as possible and not allow any user program to start. And we could send a signal to the connected Raspberry Pi to tell it to shutdown. But even then, the Build HAT will still be drawing some power, so could damage rechargeable batteries or waste non-rechargeable batteries.
