====== ROS2 Publisher Safety Level ======
This block reads the safety level id and packs it into a ROS message of type ''std_msgs::msg::String''. Each time the block is run by its time domain, this message is published under a given topic name.
<code cpp>
  RosPublisherSafetyLevel pubSL(node, "myTopic"); // create publisher block
</code>

This block must have a reference to the safety system in order to read the actual safety level. Please set the reference by calling: \\
<code cpp>
  controlSystem.pubSL.setSafetySystem(safetySystem);
</code>