[WIP][Spot] Spot's person following demo

[sktometometo]

Moved from https://github.com/jsk-ros-pkg/jsk_demos/pull/1326

This demo enables Spot to follow person.

https://user-images.githubusercontent.com/9410362/112797926-1ae3b180-90a7-11eb-892a-21e9df53716e.mp4

Prerequities

This demo requires packages below.

• [spot_ros]() with this patch
• [common_msgs]() with this patch
• [jsk_recognition]() with this patch and this patch
• [jsk_spot_startup]() with this patch

How to run

Before running this demo, please launch and prepair a controller.

• jsk_spot_bringup.launch
• object_detection_and_tracking.launch
• multi_object_detector.launch

And then, please run

roslaunch spot_person_follower demo.launch

After this, you can start following behavior by pressing L2 button of the controller. Spot will follow the nearest person at the time of pressing. If you want to stop the behavior, please press the L2 button again.