all save_pointcloud examples do not work with femto bolt

[David-Conrad]

depth_frame.get_timestamp() and depth_frame.get_timestamp_us() return both 0. Only depth_frame.get_system_timestamp() returns a value > 0

couldn't find a way to use

• timestampReset(),
• timerSyncWithHost()
• or similar functions()

(not implementet in python bindings?)