Freedrive Controller (backport #1114)

[mergify]

The PR aims at introducing the possibility of enabling the freedrive mode through the ROS2 driver. It relies on the implementation of a specific controller to handle it, in order to correctly deactivate other controllers and avoid unsafe jumps of the robot once the freedrive mode is switched off.

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This is an automatic backport of pull request #1114 done by Mergify.

[mergify]

Cherry-pick of 8d4ba94 has failed:

On branch mergify/bp/humble/pr-1114
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Changes to be committed:
	modified:   ur_controllers/CMakeLists.txt
	modified:   ur_controllers/controller_plugins.xml
	modified:   ur_controllers/doc/index.rst
	new file:   ur_controllers/include/ur_controllers/freedrive_mode_controller.hpp
	new file:   ur_controllers/src/freedrive_mode_controller.cpp
	new file:   ur_controllers/src/freedrive_mode_controller_parameters.yaml
	new file:   ur_controllers/test/freedrive_mode_controller_params.yaml
	new file:   ur_controllers/test/test_load_freedrive_mode_controller.cpp
	modified:   ur_robot_driver/config/ur_controllers.yaml
	modified:   ur_robot_driver/include/ur_robot_driver/hardware_interface.hpp
	modified:   ur_robot_driver/launch/ur10.launch.py
	modified:   ur_robot_driver/launch/ur10e.launch.py
	modified:   ur_robot_driver/launch/ur16e.launch.py
	modified:   ur_robot_driver/launch/ur20.launch.py
	modified:   ur_robot_driver/launch/ur3.launch.py
	modified:   ur_robot_driver/launch/ur30.launch.py
	modified:   ur_robot_driver/launch/ur3e.launch.py
	modified:   ur_robot_driver/launch/ur5.launch.py
	modified:   ur_robot_driver/launch/ur5e.launch.py
	modified:   ur_robot_driver/launch/ur_control.launch.py
	modified:   ur_robot_driver/test/integration_test_controller_switch.py

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   ur_robot_driver/doc/usage/controllers.rst
	both modified:   ur_robot_driver/src/hardware_interface.cpp
	deleted by us:   ur_robot_driver/urdf/ur.ros2_control.xacro

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally