Save a tiny bit of RAM by properly marking our device config
struct instances const consistently, and also add missing static
modifiers to properly isolate config/data for drivers.
* Add dedicated init priority for the sideband kscan.
* Refactor sideband code for clarity.
* Tweaks to direct kscan for clarity.
* Make sideband behavior row optional for brevity.
* Allow overriding ZMK Uno sideband behaviors.
* Better naming for gpio-key behavior triggers.
* Tweaks to scanned behavior trigger to avoid bad semaphore use,
and reduce chance of issues with slowly scanned matrixes.
* Various code cleanups of style issues.
* Promote previously local debounce code from kscan drivers to exposed
module lib, for use with other drivers as needed.
* Refactor existing kscan driver to new "public" API.
Pete Johanson