Adjustments for People Ttracker

Needs https://github.com/strands-project/strands_perception_people/pull/79 merged.

This adjusts the topic name and type the human_aware_navigation subscribes to, to the new people tracker.
Sadly this PR also contains some code that ran at the review. This has proven to work (at the review itself) and doesn't alter any other packages but just adds code.