Starts to factor out the keyboard mapper.

The more easily to clarify as to #includes, etc, and to allow for a relevant constructor.

OSBindings/Qt/keyboard.h

@@ -0,0 +1,15 @@
+#ifndef KEYBOARD_H
+#define KEYBOARD_H
+
+#include <QMainWindow>
+
+
+class KeyboardMapper {
+	public:
+		KeyboardMapper();
+		std::optional<Inputs::Keyboard::Key> keyForEvent(QKeyEvent *);
+
+	private:
+};
+
+#endif // MAINWINDOW_H