Add Kinova Gen3 Lite arm

[anashoussaini]

If you would like to see a new model added to the Menagerie collection, please provide us with the following information before sending a pull request. (Ideally, before you start working on converting or tuning the model for MuJoCo.)

URL for the existing model source (e.g. URDF):

• https://github.com/Kinovarobotics/ros_kortex/blob/noetic-devel/kortex_description/arms/gen3_lite/6dof/urdf/GEN3-LITE.urdf

License terms of the upstream model
Modified BSD License

Are you proposing to help develop and maintain the new model?
Yes, I work at Kinova, we will be maintaining this new model.

[kevinzakka]

Hi @anashoussaini, PR would be greatly appreciated!