Read and load current HW config from hardware at startup

[andrewdavidmackenzie]

ppal docs state that "Pins are constructed by retrieving them using Gpio::get.

An unconfigured Pin can be used to read the pin’s mode and logic level."

so a new option would be at start-up to read the actual HW setup, and load that and show in the UI, to not interrupt how things are working on the HW.

[andrewdavidmackenzie]

More thoughts. On a Pi, it's possible that other applications are using some of the pins I think....

so, it would be great at start-up to scan all the pins and see if we have the ability to configure them.
If we cannot, we should report them as unusuable, and disable them on the UI, maybe with some tooltip to explain why.

[andrewdavidmackenzie]

Paused for now.

See golemparts/rppal#150