Add generalized Pauli operators

Add the generalized Pauli operators characterized by the Weyl commutation relations, also called the clock and shift matrices. See, for example: - https://en.wikipedia.org/wiki/Generalizations_of_Pauli_matrices#Construction:_The_clock_and_shift_matrices - https://www.pnas.org/doi/abs/10.1073/pnas.46.4.570 - https://link.springer.com/chapter/10.1007/3-540-49208-9_27