[JTC] Deprecate start_with_holding (backport #1076)

[mergify]

It was decided not to remove start_with_holding in iron/humble, see #839 and #876.
So let's deprecate it.

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This is an automatic backport of pull request #1076 done by Mergify.

[mergify]

Cherry-pick of ea66755 has failed:

On branch mergify/bp/humble/pr-1076
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit ea66755.
  (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 <file>..." to mark resolution)
	both modified:   joint_trajectory_controller/src/joint_trajectory_controller.cpp
	both modified:   joint_trajectory_controller/src/joint_trajectory_controller_parameters.yaml

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

[christophfroehlich]

#558 hasn't been backported to humble, so no need to deprecate things here.