[idd] helper: add parser for mode settings in registry

idd/LGIddHelper/CRegistrySettings.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <optional>
+#include <vector>
+#include <string>
+#include <windows.h>
+
+struct DisplayMode {
+  unsigned width;
+  unsigned height;
+  unsigned refresh;
+  bool     preferred;
+
+  std::wstring toString();
+};
+
+class CRegistrySettings {
+  HKEY hKey;
+
+public:
+  CRegistrySettings();
+  ~CRegistrySettings();
+
+  LSTATUS open();
+  bool isOpen() { return !!hKey; }
+
+  std::optional<std::vector<DisplayMode>> getModes();
+  LSTATUS setModes(const std::vector<DisplayMode> &modes);
+};