Implemented a new API for State Transition Matrix and Jacobian Matrix computation
The new API is simpler to use and eliminates completely the need for PartialDerivativesEquations
which could be deprecated in 11.1 and removed in 12.0.
The public API is limited to call one new method in NumericalPropagator: setupMatricesComputation
that returns an opaque implementation of the new MatrixHarvester interface.
So users call setupMatricesComputation and use the harvester later on to extract the matrices from
the spacecraft states produces by the propagator along propagation.