Error using the new bag publisher with time maintanence

[Ridhwanluthra]

The bag publisher with time maintainence is being added as a part of the perception_pipeline_tutorial.

This is node is used to read a topic from a bag and publish it on a loop while using the current ROS time. It is being added to use rosbags in tutorials which contain as less as a single message. This will enable us to add any bags corresponding to any tutorial right in git.

When running the Perception Pipeline Demo, we encounter the following error (this does not break the functionality)

ros.moveit_ros_planning.planning_scene_monitor: Transform error: Lookup would require extrapolation into the future.  Requested time 1527473962.793050157 but the latest data is at time 1527473962.776993978, when looking up transform from frame [panda_link2] to frame [camera_rgb_optical_frame]
ros.moveit_ros_perception: Transform cache was not updated. Self-filtering may fail.