SPI flash sleep if bootloader >= 1.0.0 (#322)

* Retrieve and display bootloader version
- Display bootloader version on System Info screen
- Enable SPI flash sleep mode if bootloader version >= 1.0.0
* Wait for SPI flash to wakeup before starting OTA DFU

src/systemtask/SystemTask.h

@@ -73,6 +73,10 @@ namespace Pinetime {
         return nimbleController;
       };
 
+      bool IsSleeping() const {
+        return isSleeping;
+      }
+
     private:
       TaskHandle_t taskHandle;