Adds APIs for spawning deformable meshes

[Mayankm96]

Description

This MR adds schemas and spawners to create deformable bodies based on primitive shapes. It uses the latest PhysX 5.4 support for FEM simulation of deformable bodies. The MR adds the required demo and docs changes.

Type of change

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

Screenshots

deformable.mp4

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