CH9141 ADC support

[sbridger]

Just an FYI in the file in case you ever work on this again (not really any kind of request)...
I was looking for a simple cheap BLE module that comes with an ADC input, without any reprogramming. (I also needed something very light, ruling out BLE multimeters). CH9141 has AT commands to read it's single ADC pin.
https://github.com/openwch/ch9141/blob/main/CH9141DS1.PDF
https://vi.aliexpress.com/item/1005005321933143.html

A simple UI with V scaling to read the ADC would be good