Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

utilities/headtrack.h

@@ -0,0 +1,14 @@
+#pragma once
+
+class headtrack
+{
+    int joy_id = -1;
+
+    void find_joy();
+    float get_axis(const float *data, int count, int axis, float mul);
+
+public:
+    headtrack();
+
+    void update();
+};