Added missing doxygen comments and removed explicit init function

include/vkcv/BufferManager.hpp

include/vkcv/Core.hpp

include/vkcv/DrawcallRecording.hpp

src/vkcv/BufferManager.cpp

src/vkcv/ComputePipelineManager.hpp

src/vkcv/Context.cpp

src/vkcv/Core.cpp

src/vkcv/DescriptorManager.cpp

src/vkcv/DescriptorManager.hpp

src/vkcv/DrawcallRecording.cpp

src/vkcv/GraphicsPipelineManager.hpp

src/vkcv/ImageManager.hpp

src/vkcv/PassManager.hpp

src/vkcv/SamplerManager.hpp

src/vkcv/SwapchainManager.hpp

src/vkcv/WindowManager.hpp