Query people from ED

[ar13pit]

1. In SMACH states The mechanism to query people from ED is something like (from human_interaction/find_person_in_room.py):

image_data = robot.perception.get_rgb_depth_caminfo()
success, found_people_ids = robot.ed.detect_people(*image_data)
found_people = [self._robot.ed.get_entity(id) for id in found_people_ids]
found_names = {person.id: person for person in found_people}

Such statements are used in multiple places inside human_interaction module and also in challenges (serving_drinks). This can be put up as an interface to get certain properties of a person. The same lines must not be called in multiple places.

2. In rviz Deleted people entities are not removed from the visualizer. It is impossible to understand whether the displayed people are new or deleted old entities.