Flight Tasks: add new trajectory smoothing flight task & library

src/lib/FlightTasks/CMakeLists.txt

.../FlightTasks/tasks/ManualPositionSmoothVel/CMakeLists.txt

...alPositionSmoothVel/FlightTaskManualPositionSmoothVel.cpp

...alPositionSmoothVel/FlightTaskManualPositionSmoothVel.hpp

src/lib/FlightTasks/tasks/Utility/CMakeLists.txt

src/lib/FlightTasks/tasks/Utility/VelocitySmoothing.cpp

src/lib/FlightTasks/tasks/Utility/VelocitySmoothing.hpp

src/modules/mc_pos_control/mc_pos_control_main.cpp

src/modules/mc_pos_control/mc_pos_control_params.c