Refactor path tracing and material rendering system

Added a new enum `path_state` and a struct `path_output` in `Common.h` to manage path tracing states and outputs.
Added a new `simple_lit_render_loop` function in `SimpleLit.c` to handle rendering for simple lit materials, integrating light contributions and BSDF evaluations.

Changed the function signatures in `Light.h` to use `path_output` instead of `vec3s` for BSDF evaluations.
Changed the `evaluate_bsdf_directional` function in `LightEvaluation.h` to return `path_output` instead of `vec3s`.
Changed the `evaluate_bsdf_sky` function in `LightEvaluation.h` to return `path_output` and updated its implementation accordingly.
Changed the function signature of `evaluate_bsdf_const_sky` in `SkyLight.h` to return `path_output` and modified its implementation to match.

Removed several old BSDF-related functions in `Material.c` that are no longer needed due to the new structure.

Updated the `material_create` function in `Material.c` to accept the new render loop function pointer.
Updated the `path_trace` function in `PathTracing.c` to utilize the new `path_output` structure for managing light contributions and state transitions during path tracing.
Updated the `evaluate_bsdf_directional` function in `LightEvaluation.c` to return `path_output` and adjusted its internal logic to populate the output structure.
Updated the `evaluate_bsdf_const_sky` function in `SkyLight.c` to return `path_output` and modified its logic to handle light contributions correctly.
Updated the intensity of the sky light to `0.0f` during scene setup in `main.c`, effectively disabling it.

header/Rendering/Renderer.h

@@ -1,4 +1,4 @@
-# ifndef RENDERER_H
+#ifndef RENDERER_H
 #define RENDERER_H
 
 #include "Rendering/Debug.h"