Porting 5_3_X HI reco updates to 7_2_X

The HI RECO updates that were previously implemented in 5_3_X are re-implemented in 7_2_X.

 don't copy-paste the same access many times
```
auto const & aVtx = (*recoVertices)[greatestvtx];
vx = aVtx.position().x();
...
```