feature(split): behavior locality support.

* 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.

app/src/behaviors/behavior_reset.c

@@ -36,6 +36,7 @@ static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
 
 static const struct behavior_driver_api behavior_reset_driver_api = {
     .binding_pressed = on_keymap_binding_pressed,
+    .locality = BEHAVIOR_LOCALITY_EVENT_SOURCE,
 };
 
 #define RST_INST(n)                                                                                \