Separate windows shell interaction into it's own file

AsuroTool/WindowsShell.h

@@ -0,0 +1,8 @@
+#pragma once
+#include <ImguiBase.h>
+
+void initShell(DrawData& drawData);
+
+void cleanupShell(DrawData& drawData);
+
+LRESULT trayIconEventHandler(int code, WPARAM wParam, LPARAM lParam);