Final Repository Cleanup

[DanielChaseButterfield]

Features

• Added information on accessing the Simulated A1 dataset to README.md and paper/README.md, so that more people are aware of the dataset and it's features, and are able to manually download the rosbag files.
• Added more explanation into the different URDF files available in the repository and a caution to double check the URDF file before use.
• Added src/mi_hgnn/datasets_py/README.md and src/mi_hgnn/datasets_py/CustomDatasetTemplate.py to make it easy for users to integrate their own datasets.
• Updated README.md with specific instructions on how to apply the MI-HGNN to a new robot/dataset, and added a figure from the ICRA submission video demonstrating it's applicability to different robots.

Deletions

• Removed git submodule for the HyQ that has since been set to private or deleted by original owner.

Refactors

• Moved the online link of the Deprecated A1 Datasets used for test cases to Dropbox.
• Update testGraphParser.py to use MiniCheetah URDF instead of HyQ URDF (as that was removed).

Bug Fixes

• Updated a docstring in graphParser.py that had an erroneous comment.