Enhanced URDF Model

[exo-core]

Fixes

Description of the changes:

• Created new meshes and updated the URDF model as described in #237

Required before submitting a Pull Request:

• [x] I reviewed CONTRIBUTING.md
• [x] I built my changes locally
• [x] I tested my changes with a device
• [ ] I changed both the ROS1 and ROS2 branches

I tested changes on:

• [ ] Windows
• [x] Linux
• [x] ROS1
• [ ] ROS2

[ghost]

All CLA requirements met.

[ooeygui]

Thank you for the contribution. Looks good to me! I'd love to get another :+1: from the community before I pull this in.