Automatic extraction of arc initial states

[z-afzal]

To perform estimation for an empty body, an ephemeris is required. Ideally, Tudat should create this ephemeris automatically when not provided by the user. However, this feature is not working as expected for multi-arc scenarios.

Also, the automatic extraction of arc initial states from the propagator settings is not yet implemented. As a result, users need to manually ensure that the initial states are compatible with the arc configurations. automatically extracts arc initial states from the propagator settings would enhance the usability of Tudat for performing simulations and estimations.