RGBD Phases added

Due to the challenge being all simulation an RGBD track has been added. Two new phases have been added to support the track (dev and challenge). The robothor-challenge github repo has also been updated to include a new script to evaluate an RGBD model. If you would like to incorporate the depth data into training for the RGB track (existing track), you may do so by updating the challenge_config.yaml to match the challenge_config_rgbd.yaml. Be aware that the depth frame will not be available during evaluation for the RGB track.