add pass manager.

config/Sources.cmake

include/vkcv/Core.hpp

include/vkcv/Handles.hpp

include/vkcv/PassConfig.hpp

include/vkcv/Pipeline.hpp

projects/first_triangle/src/main.cpp

src/vkcv/Core.cpp

src/vkcv/PassConfig.cpp

src/vkcv/PassManager.cpp

src/vkcv/PassManager.hpp

src/vkcv/Pipeline.cpp