Replaced pixelVertices by firstStepPrimaryVertices made from iter0 tracks

Remove pixelTracks and pixelVertices from reco sequence.
Replaced with the higher quality firstStepPrimaryVertices introduced together with JetCoreTracks in 7.2

Minor regression observed.
One may even pretend that fake-rate decreases and conversions benefit.

It seems like we are converging this change is a way to go.
So, with this in mind, please remove all these commented out lines (I will not repeat for O(10) more cases in this PR)