Pr functional

Moved Pr code and TrackEventFitter algo to functional. This includes PrForwardTracking, PrHybridSeeding, PrStoreClusters, PrVeloUT, PrMatchNN as well as TrackEventFitter algorithms. In some cases, quite some refactoring was needed so one needs to carefully check the diffs of the tests results before merging this. Note that this depends on Gaudi merge request Gaudi!58 (merged)