Userguide and tutorial JAX transformation of Pulse Scheduler

[to24toro]

Summary

This tutorial and user guide are related to https://github.com/Qiskit/qiskit-dynamics/pull/149. In the user guide,

• show some pulses using ScalableSymbolicPulse.
• jax-jit these pulses.

In the tutorial,

• show the optimization of a single X gate defined by pulse schedulers. The tutorial is much overlapping with the configuration of https://qiskit.org/documentation/dynamics/tutorials/optimizing_pulse_sequence.html . Whether or not merging this PR depends on the discussion.

Details and comments

Currently, a new class ScalableSymbolicPulse which is a subclass of SymbolicPuse and assumed to hava a scalable form was introduced. So I use this class in this PR. However, I use the SymbolicPulse in https://github.com/Qiskit/qiskit-dynamics/pull/149. I would like to discuss which we should use.

[to24toro]

I modified, improved English phrases and also add sphinx refs at https://github.com/Qiskit/qiskit-dynamics/pull/194/commits/55ff5bc26d351eb011a38a6877a0b28e41fb3b21 .