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.

A general comment better not use the handle directly, instead
```
const EcalRecHitCollection& ebHitsC = *ebHits;
```
similar in other cases.
here the cost isn't very large though.