Enable option of fitting v1 tracks with VeloKalman

We persist PVs (RecVertex) and their tracks (v1 tracks), but refitting them is currently only possible with the PrKalman or TrackMasterFitter. This breaks the reproducibility of what happens in HLT2, which uses tracks fitted with the VeloKalman. The functions in the VeloKalmanHelpers are unfortunately specific to the SoA containrs.

Ideally we fix this and make it also available for a TrackStateInit-like tool to re-initialise VELO tracks.