Kf with nested material interaction

The KF smoothing formalism needs to have knowledge of the Jacobian at each propagated surface with material. The current KF only creates track state at those propagated surfaces with measurement on it and the Jacobian at other in-sensitive surfaces are not 'recorded' properly. Thus, the Jacobian used in the current KF smoothing could not be right.

Changes included in this MR:

• Add the type Flags for track state
• Extend the KalmanActor to include material interaction based on !719 (merged) and create track state on each propagated surface with material: -- For surfaces with 'valid' measurement, there is no change of the meaning of the predicted and filtered parameter; -- For surfaces without 'valid' measurement, the filtered parameter will be obtained by updating the predicted parameter with material effects. In this way, the current smoothing formalism will still be valid.
• Add a covariance helper to correct the smoothing covariance matrix to be semi-positive definite.
• Add a new type of KalmanFitterError when the propagation passes through no detector at all to prevent further retrieving of the Kalman Fitter result.