Overhaul Jacobians matrices computation API

Jacobians matrices are currently extracted from propagators using several classes extending AbstractJacobiansMapper and that are specialized for each propagator. TLE propagator has an analytical implementation, DSST propagator has a mixed implementation and nulmerical propagator has an implementation based on using the old monolithic class PartialDerivativesEquations that implements AdditionalEquation and has a very awkward API (auto-add itself to the propagator, but needs to wrap the initial state before reinitializing the propagator with its return value…)

A more user-friendly API would be welcome, where propagators themselves would provide a getJacobiansMapper method that would trigger computation internally as anyway each propagator already does the computation in specific ways.

A complete API overhaul could be done only on a major version (i.e. 12.0).