Factor out path joint-space jump check

[marioprats]

Description

This change factors out the path joint-space jump detector of CartesianInterpolator into a separate function called hasJointSpaceJumps(), so that it can be used in a different context.

The new function returns an std::optional<int> with the path index where the jump happens, or nothing if there are no jumps.
The CartesianInterpolator::checkJointSpaceJump function is then updated to use the free function underneath, and truncate the path, etc, i.e., it keeps the same behavior.

In addition to this, there's two API-breaking changes:

1. Remove the public CartesianInterpolator::checkRelativeJointSpaceJump and CartesianInterpolator::checkAbsoluteJointSpaceJump, since these can be easily achieved with the more general CartesianInterpolator::checkJointSpaceJump, therefore exposing a smaller API footprint.
2. Update the JumpThreshold struct with named builder methods (disabled(), relative() and absolute()) instead of public constructors. This should be more readable and less error-prone.

Migrating old code to the new API should be straight-forward:

• JumpThreshold() -> JumpThreshold::disabled()
• JumpThreshold(2.0) -> JumpThreshold::relative(2.0)
• JumpThreshold(1.0, 2.0) -> JumpThreshold::absolute(1.0, 2.0)

Finally, there's a few cosmetic changes in documentation and a semantic rename traj -> path, since these methods operate on paths (sequence of RobotState, as opposed to RobotTrajectory, which should take timing into account).

Closes #2272.

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[codecov]

Codecov Report

Attention: 33 lines in your changes are missing coverage. Please review.

Comparison is base (09019d2) 50.32% compared to head (6d379dc) 50.38%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2506      +/-   ##
==========================================
+ Coverage   50.32%   50.38%   +0.07%     
==========================================
  Files         391      391              
  Lines       31983    31992       +9     
==========================================
+ Hits        16091    16117      +26     
+ Misses      15892    15875      -17     

Files	Coverage Δ
...nclude/moveit/robot_state/cartesian_interpolator.h	45.46% <0.00%> (-23.29%)	⬇️
...it_core/robot_state/src/cartesian_interpolator.cpp	35.53% <61.91%> (-0.70%)	⬇️

... and 3 files with indirect coverage changes

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[marioprats]

Ah, I think MTC is failing in CI because of the API change. Will probably need to keep the old JumpThreshold constructors public and mark them as deprecated.

[sjahr]

Nice work! Just a couple of questions and nits and then this is ready to be merged