fix(split): Use queue/work for peripheral events.

* Avoid corruption by using work to process
  peripheral key position events on the main
  work thread, like local kscan events are.
* Fixes #221

app/Kconfig

@@ -94,11 +94,19 @@ config ZMK_SPLIT_BLE
 
 if ZMK_SPLIT_BLE
 
-config ZMK_SPLIT_BLE_ROLE_CENTRAL
+menuconfig ZMK_SPLIT_BLE_ROLE_CENTRAL
 	bool "Central"
 	select BT_CENTRAL
 	select BT_GATT_CLIENT
 
+if ZMK_SPLIT_BLE_ROLE_CENTRAL
+
+config ZMK_SPLIT_BLE_CENTRAL_POSITION_QUEUE_SIZE
+	int "Max number of key position state events to queue when received from peripherals"
+	default 5
+
+endif
+
 if !ZMK_SPLIT_BLE_ROLE_CENTRAL
 
 config ZMK_USB