Add HidDriver base and small HidGLFW driver

backends/include/pd_system/hid_glfw.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <pd/drivers/hid.hpp>
+
+typedef struct GLFWwindow GLFWwindow;
+
+namespace PD {
+class HidGlfw : public HidDriver {
+ public:
+  HidGlfw(GLFWwindow* window);
+  ~HidGlfw();
+
+  void Update() override;
+
+ private:
+  struct Impl;
+  Impl* impl;
+};
+}  // namespace PD