[#55] Add mipmap generation

include/vkcv/Core.hpp

include/vkcv/Image.hpp

modules/gui/src/vkcv/gui/GUI.cpp

projects/first_mesh/src/main.cpp

projects/voxelization/src/main.cpp

src/vkcv/BufferManager.cpp

src/vkcv/Core.cpp

src/vkcv/Image.cpp

src/vkcv/ImageManager.cpp

src/vkcv/ImageManager.hpp

src/vkcv/SamplerManager.cpp