Msg update

The main purpose of this merge request was to incorporate our new coneArray.msg but I've also done some other stuff. I have used this branch in the development of the recent changes to planning & control so I have tested it quite extensively.

@pmacg and @rokasgie to review

Full list of changes:

• Incorporated @rokasgie's improvements to the cone_ground_truth node i.e. they no longer get stuck in RViz.
• I've updated all tracks to the new format I started using during my thesis. Instead of having many identical meshes in a single Gazebo model file, the models of the tracks now have just have nested cone models which simplify the models, allow for faster loading and also make track CSV generation easier.
• Updated tracks to now include big orange cones wherever needed.
• Made a script that automatically generates track CSV files with cone locations used for ground truth cone simulation.
• Made the cone_ground_truth node to work with the Odometry message instead of the transform. This fixes the previous issue we had where localisation development and cone ground truth simulation were mutually exclusive.
• Made the cone_ground_truth node to simulate cone detections in a parameterizable field of view (FOV). This was done as per @vivkr 's request and our commitment to go camera-mainly this competition.

Housecleaning:

• General housecleaning and remove unnecessary files.
• Renamed the extractor node to cone_ground_truth as it is more explanatory of what the node does.
• Fixed ROS dependencies of all packages inside this repo
• Added Python requirements.txt dependencies handling as per new agreement
• Updated the general README