Code quality: Fix header guards consistency

Adds `header_guards.sh` bash script, used in CI to validate future
changes. Can be run locally to fix invalid header guards.

modules/raycast/lightmap_raycaster.h

@@ -74,4 +74,4 @@ public:
 	~LightmapRaycasterEmbree();
 };
 
-#endif
+#endif // LIGHTMAP_RAYCASTER_H

modules/raycast/raycast_occlusion_cull.h

@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#ifndef OCCLUSION_CULL_RAYCASTER_H
-#define OCCLUSION_CULL_RAYCASTER_H
+#ifndef RAYCAST_OCCLUSION_CULL_H
+#define RAYCAST_OCCLUSION_CULL_H
 
 #include "core/io/image.h"
 #include "core/math/projection.h"
@@ -192,4 +192,4 @@ public:
 	~RaycastOcclusionCull();
 };
 
-#endif // OCCLUSION_CULL_RAYCASTER_H
+#endif // RAYCAST_OCCLUSION_CULL_H

modules/raycast/static_raycaster.h

@@ -61,4 +61,4 @@ public:
 	~StaticRaycasterEmbree();
 };
 
-#endif
+#endif // STATIC_RAYCASTER_H