Clean code

src/input/data.cpp

src/input/pdptw_data.cpp

src/lns/constraints/capacity/capacity_constraint.cpp

src/lns/constraints/time_window/time_window_constraint.cpp

src/lns/modification/pair/insert_pair.cpp

src/lns/modification/pair/remove_pair.cpp

src/lns/solution/route.cpp

src/lns/solution/solution.cpp