Use IK from RobotModel

[simonschmeisser]

Currently TracIK is used but for most industrial robots analytical solvers exist (opw, ur_kinematics, ikFast, ...). Those are one hand several orders of magnitude faster and more importantly have a higher success ratio.

[jrgnicho]

TracIK was chosen because it allows evaluating unconstrained goals with relative ease

[kokkalisko]

@jrgnicho I would like to adjust the planner to use opw_kinematics. I do not understand why TRAC-IK was preferred. Can you provide some additional info? Do you mean that this inverse kinematics solver was preferred because MoveGroup IK imposes some precision criteria?