Support pin muxing in Zephyr through IOBroker

[tannewt]

IOBroker is a new zephyr module that maps package pins to peripherals and uses Zephyr's dynamic pinctrl to prep a device for use. It does resource use tracking for pads and peripherals/devices as well.

This does have a couple issues that need to be fixed in follow up:

• I2C scanning on the nRF54LM20 is broken in Zephyr. Works on the nRF52840 though.
• No bulk resets implemented so objects that aren't finalized will leak pins and peripherals. Will follow up with a macro to enable finalizers in shared-bindings (and disable never_reset).

[dhalbert]

This seems quite clean to me, thanks! Various questions and requests in the review.

It's too bad you have to undo the supplied device tree entries, but without defining all-new boards, I don't see a way around it. This is going to be a maintenance issue when they change.

[tannewt]

It's too bad you have to undo the supplied device tree entries, but without defining all-new boards, I don't see a way around it. This is going to be a maintenance issue when they change.

Yeah, some zephyr stuff is weird. I'm hopeful LLMs + hardware in the loop will make maintenance easier.

[dhalbert]

One q

[dhalbert]

Very nice solution!