Implement `commutator` routines for the `SparseLabelOp`

[mrossinek]

trafficstars

What should we add?

It would be useful to have (anti-/double-)commutator routines for SparseLabelOp instances, similar to those available in qiskit.opflow.

The implementation is likely almost identical (calling .simplify() instead of .reduce()) and should be placed into qiskit_nature.second_q.operators.commutators. Unittests should be added accordingly.

[javabster]

You can assign this to me! 😄