Adds uv support as an alternative to conda in isaaclab.sh

[KyleM73]

Description

This PR adds support for uv as an alternative to conda for managing python dependencies. Uv is significantly faster than conda and has many useful tools.

If users wish to use the uv workflow they will need to have uv installed, but otherwise no additional dependencies are added.

Docs should be updated to describe this option. There may need to be more work done to clean when deactivating the environment. Uv does not support pre and post activation hooks like conda so cleaning up the environment variables is slightly more tricky. I would greatly appreciate feedback to improve this workflow!

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist

• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[Mayankm96]

Mainly NITs. Could you also update the setup instructions for UV? :)

It would be good to extend the support to Windows. If you don't have access to a Windows machine, could you please make a ticket so our team can look into it? Thank you!

[KyleM73]

I'm working on updating the docs accordingly. I don'y have access to a Windows machine so would greatly appreciate some help setting it up in the .bat file. uv is supported on Windows so the setup should be similar.

[KyleM73]

Ok I believe the docs have been updated as needed. Only the .bat needs to be updated. The uv install should be the same as linux, just the terminal commands for Windows is different (and maybe the method I'm using to alias isaaclab when in the venv). Since I can't test it I haven't edited the .bat file at all.