Add new screen that allows the user to manually validate the new firmware he's just OTA'ed.

Still need to find a way to display this screen when needed.

src/Components/FirmwareValidator/FirmwareValidator.cpp

@@ -0,0 +1,20 @@
+#include <drivers/InternalFlash.h>
+#include <hal/nrf_rtc.h>
+
+#include "FirmwareValidator.h"
+
+using namespace Pinetime::Controllers;
+
+bool FirmwareValidator::IsValidated() const {
+  auto* imageOkPtr = reinterpret_cast<uint32_t *>(validBitAdress);
+  return (*imageOkPtr) == validBitValue;
+}
+
+void FirmwareValidator::Validate() {
+  if(!IsValidated())
+    Pinetime::Drivers::InternalFlash::WriteWord(validBitAdress, validBitValue);
+}
+
+void FirmwareValidator::Reset() {
+  NVIC_SystemReset();
+}

src/Components/FirmwareValidator/FirmwareValidator.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <cstdint>
+
+namespace Pinetime {
+  namespace Controllers {
+    class FirmwareValidator {
+      public:
+        void Validate();
+        bool IsValidated() const;
+
+        void Reset();
+      private:
+        static constexpr uint32_t validBitAdress {0x7BFE8};
+        static constexpr uint32_t validBitValue {1};
+    };
+  }
+}