More Flexible Inputs to PrKalmanFilter
Makes use of new common hit class LHCb::Pr::Hits that is templated in HitType. This is useful to avoid passing all hit containers to the PrKalmanFilter even when fitting a track that only has hits from one of them. Thus with this MR PrKalmanFilter accepts only hit containers needed to fit a track type. Other changes are mostly fixing includes that changed because of changes in LHCb and removing LHCb::Pr::UT::HitHandler.
Related to #303
Goes with LHCb!3473 (merged), Allen!818 (merged) and Moore!1456 (merged)