Verify the main app mostly sleeps

This validates that the main watch app spends at
least 99.5% of it's time sleeping in the first 10
seconds.

firmware/Bsp/Drivers/LowPower.h

@@ -22,6 +22,7 @@
 #pragma once
 
 #include "Bsp/ReturnCode.h"
+#include "Bsp/Drivers/GpioDriver.h"
 
 extern uint32_t wakeups;
 
@@ -32,10 +33,14 @@ public:
     LowPower() = delete;
 
     static BSP::ReturnCode init();
+    static BSP::ReturnCode init(GpioPin &timing_pin);
+
     static BSP::ReturnCode sleep();
     static BSP::ReturnCode stop();
     static BSP::ReturnCode enable_debug();
     static BSP::ReturnCode disable_debug();
+
+    static GpioPin *m_timing_pin;
 };
 
 }