Add effort command interface to all joints (backport #302)

[mergify]

This is a part of bringing torque_control for UR to ROS.

This is currently in a beta phase (see https://github.com/UniversalRobots/Universal_Robots_Client_Library/tree/torque_control?tab=readme-ov-file#universal-robots-client-library), hence the draft status.

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This is an automatic backport of pull request #302 done by Mergify.

[mergify]

Cherry-pick of 9816fa8 has failed:

On branch mergify/bp/humble/pr-302
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit 9816fa8.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   urdf/inc/ur_joint_control.xacro

no changes added to commit (use "git add" and/or "git commit -a")

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