Added doxygen comments to handles and adjusted enum classes

include/vkcv/Buffer.hpp

include/vkcv/Handles.hpp

include/vkcv/Image.hpp

include/vkcv/Logger.hpp

include/vkcv/PushConstants.hpp

include/vkcv/Result.hpp

include/vkcv/Sampler.hpp

include/vkcv/ShaderProgram.hpp

include/vkcv/Surface.hpp

include/vkcv/Swapchain.hpp

include/vkcv/Window.hpp