- implement shutdown (deep sleep forever) on ESP32

- Clean up shutdown and delayed shutdown code conditionals.
- clean up inputbroker includes

src/input/kbI2cBase.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include "InputBroker.h"
-#include "SinglePortModule.h" // TODO: what header file to include?
+#include "concurrency/OSThread.h"
 #include "Wire.h"
 
 class KbI2cBase : public Observable<const InputEvent *>, public concurrency::OSThread