Simplify KDL joint weights parameters

[sea-bass]

In #2750 we introduced a stop-gap for fixing the KDL IK plugin parameters so that CI passes due to some breaking changes in generate_parameter_library.

Ideally, we should change generate_parameter_library to support a simpler way of expressing these weights, for example:

  weights:
    joint1: 2.0
    joint5: 1.5

[github-actions]

This issue is being labeled as stale because it has been open 45 days with no activity. It will be automatically closed after another 45 days without follow-ups.

[sjahr]

I think this got addressed by #2750 (comment). @sea-bass feel free to re-open this issue if that's not the case