Add ros2 support for franka fr3

[AndreasJosefGassner]

Summary

This PR adds support for ROS 2 Humble for the Franka FR3 robot arm, including compatibility with either the Franka Hand or the Robotiq 2F-85 gripper.

Details

• A new ros2/ directory has been introduced to house all ROS 2-specific setup:

  • Contains the required source files (src/) for ROS 2 packages.
  • Includes a development container (devcontainer) for streamlined development.
  • Includes a dedicated README file with setup instructions and detailed descriptions of the newly added packages.

• Minor updates were made to the top-level README to reflect the new ROS 2 support.

[AndreasJosefGassner]

Overall looks good to me! Can you check to see why the github actions fails?

Seems like a newer version of actions/setup-python fixes the problem. I changed it to v5, now they are running again.