Added features for computing ground truth and improving results

[vvasco]

This PR adds several features for exposing ground truth and measured values and improving the results of the motion analysis. Specifically we now:

• expose the ground truth and measured time, success rate, and interaction status;
• include an overhead light to the tug scenario world to improve open pose results;
• compute the number of steps based on the feet y coordinate, rather than adopting the skeleton's planes which are quite noisy especially when turning;
• rely on the hip to check if the finish line is crossed, rather than on both feet.

With @AlexAntn we have developed and used these features to generate the results for Frontiers' paper.

[pattacini]

Waiting for the CI and then will merge.