Add tutorial Load custom quadruped robot environments using Gymnasium/MuJoCo/Ant-v5 framework

[Kallinteris-Andreas]

Description

Adds a (hopefully) comprehensive tutorial on how to load quadruped robot models.

I would like a proofreading review, any comments/questions/requests are welcome (dumb questions are also welcome).

Should this be in the tutorials/gymnasium_basics section?

Also need to add it tutorial's toctree (which I can not figure out how to do it)

Type of change

• Documentation change (no code changed)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[pseudo-rnd-thoughts]

Amazing, thanks for the tutorial

I have tried remaking the website (make html) but the tutorial doesn't appear in gymnasium_basic, I suspect that the tutorials need to all be python files

[Kallinteris-Andreas]

1. renaming the file to .py or .rst does not fix the toctree, opening file:///home/vm/Gymnasium/docs/_build/dirhtml/tutorials/gymnasium_basics/load_quadruped_model/index.html works (change the path to gymnasium on your computer)
2. I have decided to convert the PR to a draft to double-check the values. (the text is perfectly fine, feel free to review to it)

[pseudo-rnd-thoughts]

Looks good, my suggested changes