Add user-friendly topic for pointcloud

Using `ros2 echo pointCloud` doesn't provide any useful information. For cases where it is helpful to have the numerical values of individual markers, it would be helpful to have a topic with a simple pointarray.

No source file, test, or entry point is named. Start by locating where the pointcloud topic is published, then determine how a topic exposing numerical values for individual markers should be represented and consumed. Done means the new simple point-array topic provides useful marker values when echoed.

Written by the indexing model from the issue text.