Franka Ign ROS 2 Control

This package is based on https://github.com/ros-controls/gz_ros2_control/tree/humble

One main difference is that for Franka robots in gravity compenstation is added in the hardware side. To be consistent with our examples, we added the gravity torque term for each joint in the ign_system.cpp

\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^ Changelog for package franka_ign_ros2_control \^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^

0.7.9 (2024-06-26)

• Originates from [ign_ros2_control]{.title-ref} https://github.com/ros-controls/gz_ros2_control/tree/humble/ign_ros2_control.
• Fixed the effort interface reading by https://github.com/ros-controls/gz_ros2_control/pull/186.
• Effort command sends by default the torques from gravity term.
• Original authors: Alejandro Hernández Cordero, Louise Poubel, Vatan Aksoy Tezer