Use pink for ik
Summary
There is a dedicated library for inverse kinematics with pinocchio: pink. It could be used for a potential ik speedup.
Result
In a quick trial, pink was 5-6 times slower than the implemented ik_jacobian method. As Timor is currently optimized for monolithic industrial manipulators, the additional capabilities of pink cannot unfold their full potential and an integration is discarded for the moment.