* GATT characteristic allowing passng data + behavior
label to invoke the behavior on the peripheral side.
* Behaviors have a locality setting to specify where they run.
* Build reset/power/RGB on peripheral.
* Use lesser-known DT features to skip behaviors not referenced
in the user keymap
* Update the behaviors to skip code if no nodes found.
* Remove some empty config/data structs where unused in
behaviors.
Peter Johanson