* Now that device init of kscan sideband is in POST_KERNEL stage,
use a separate SYS_INIT for auto enabling the device so processing
of early/initial presses from referenced toggle mode kscan devices
occurs at the proper time during init.
* If using a sideband kscan device to wrap a native kscan device,
ensure the inner kscan device is also wakeup enabled to it can
be waken from a deep sleep state by key press.
* In order to be sure the rest of the system is fully ready before
intializing, because init may result in immediate events being
triggered when used with toggle direct kscan inner devices.
* 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.
* Instead of gpio key behavior trigger, add new kscan driver that
decorates/wraps a given kscan driver and will invoke basic system
behavior assigned to a given row + column, without the need for keymap
mapping in the matrix transform, bypassing keymaps entirely.
Peter Johanson
Maxime Vincent