Add Torobo and Torobo Hand

[mamoruoka]

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)
URDF file is not open-sourced yet, but xml file is open-sourced. To test the model, please refer to the README in torobo_mujoco.
Torobo: https://github.com/TokyoRobotics/torobo_mujoco/blob/main/robots/torobo2/torobo2_with_hand.xml
Torobo Hand: https://github.com/TokyoRobotics/torobo_mujoco/blob/main/robots/hand_v4/hand_v4.xml

License terms of the upstream model
BSD 3-Clause License

What do you think is required to convert and tune this model for MuJoCo?
The model is already converted for MuJoCo.

Are you proposing to help develop and maintain the new model?
Yes

[kevinzakka]

Hi @mamoruoka, lovely models. Feel free to open a PR!

[mamoruoka]

@kevinzakka
Thank you for your replay.
I will open a PR next week!