Add decay-tree recombiner, generalise the LHCbIDOverlap functionality and general code refactoring

This MR adds functionality to further use the track refitting in a more convenient manner. The goal is to have an algorithm that takes care of decay trees, in which one may want to refit the decay vertices with updated track parameters.

Because the TrackMasterFitter and the PrKalman do not share a proper common interface, and for the sake of splitting up functionality into different bits, I went through the path of splitting the track fitting itself from the recombining of a decay tree. To help the standard use-case, a Moore MR (Moore!3622 (merged)) provides the helper function to chain the pieces together for the normal sequence of events.

TODO before undrafting:

• find a better place for the usedState(Track&) function, that now is copy/pasted from the FunctionalParticleMaker, but is also used in e.g. the Bremmaker.
• add a DaVinci test that uses this
• ideally decide on whether we can invert a 2D relation table, or output two 1D tables. If we don't decide, try and keep API unchanged

Goes with:

• LHCb!4637 (merged)
• Moore!3622 (merged)
• DaVinci!1119 (merged)