[#96] Added doxygen comments to define modules as groups

modules/asset_loader/include/vkcv/asset/asset_loader.hpp

modules/camera/include/vkcv/camera/Camera.hpp

modules/camera/include/vkcv/camera/CameraController.hpp

modules/camera/include/vkcv/camera/CameraManager.hpp

modules/camera/include/vkcv/camera/PilotCameraController.hpp

.../camera/include/vkcv/camera/TrackballCameraController.hpp

modules/gui/include/vkcv/gui/GUI.hpp

modules/material/include/vkcv/material/Material.hpp

modules/meshlet/include/vkcv/meshlet/Forsyth.hpp

modules/meshlet/include/vkcv/meshlet/Meshlet.hpp

modules/meshlet/include/vkcv/meshlet/Tipsify.hpp

modules/scene/include/vkcv/scene/Bounds.hpp

modules/scene/include/vkcv/scene/Frustum.hpp

modules/scene/include/vkcv/scene/Mesh.hpp

modules/scene/include/vkcv/scene/MeshPart.hpp

modules/scene/include/vkcv/scene/Node.hpp

modules/scene/include/vkcv/scene/Scene.hpp

modules/shader_compiler/include/vkcv/shader/Compiler.hpp

modules/shader_compiler/include/vkcv/shader/GLSLCompiler.hpp

...es/upscaling/include/vkcv/upscaling/BilinearUpscaling.hpp