Hello,

This MR is implementing a timing cut on the cells that seed the pi0 topoclustering, as discussed [at the reconstruction meeting](https://indico.cern.ch/event/1086705/contributions/4568518/attachments/2330839/3972063/RIG_timeCut_19_10_21.pdf).
The timing cut for our standalone topoclustering is controlled with the same CaloRec flags as for standard topoclustering, with the exception of the hardcoded `TimeCutUpperLimit` value (currently, `TimeCutUpperLimit` is also hardcoded wherever used, this might be harmonised by introducing a new CaloRec flag is a same value suits all clients).

The MR was tested with q431 and q221 on 40 events.
By default, as the timing cut is not enabled, the tau reconstruction output is unchanged.
When switching it on (`--preExec "RAWtoESD:from CaloRec.CaloTopoClusterFlags import jobproperties; jobproperties.CaloTopoClusterFlags.doTimeCut=True; jobproperties.CaloTopoClusterFlags.extendTimeCut=True; jobproperties.CaloTopoClusterFlags.useUpperLimitForTimeCut=True"`), we do see a difference for q431. For q221, as this is without pileup, the observed stability is rather encouraging.

q431 without timing cut:
```
     292.812 kb      111.966 kb        2.799 kb        2.615       40  CaloCalTopoClusters_links (CaloClusterCellLinkContainer_p1) [CaloTopo]
     302.836 kb      112.271 kb        2.807 kb        2.697       40  TauPi0Clusters_links (CaloClusterCellLinkContainer_p1) [tau]
     277.527 kb      133.037 kb        3.326 kb        2.086       40  TauPi0Clusters (DataVector<xAOD::CaloCluster_v1>) [tau]
    1760.537 kb      455.399 kb       11.385 kb        3.866       40  CaloCalFwdTopoTowers (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
    2710.928 kb     1074.640 kb       26.866 kb        2.523       40  CaloCalTopoClusters (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
     453.956 kb      105.116 kb        2.628 kb        4.319       40  TauJets (DataVector<xAOD::TauJet_v3>) [tau]
```

q431 with timing cut:
```
     233.249 kb       88.531 kb        2.213 kb        2.635       40  TauPi0Clusters_links (CaloClusterCellLinkContainer_p1) [tau]
     250.630 kb       97.291 kb        2.432 kb        2.576       40  CaloCalTopoClusters_links (CaloClusterCellLinkContainer_p1) [CaloTopo]
     224.163 kb      105.498 kb        2.637 kb        2.125       40  TauPi0Clusters (DataVector<xAOD::CaloCluster_v1>) [tau]
    1522.887 kb      398.415 kb        9.960 kb        3.822       40  CaloCalFwdTopoTowers (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
    1962.282 kb      774.669 kb       19.367 kb        2.533       40  CaloCalTopoClusters (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
     401.291 kb       92.599 kb        2.315 kb        4.334       40  TauJets (DataVector<xAOD::TauJet_v3>) [tau]
```

q221 without timing cut:
```
     268.911 kb      119.671 kb        2.992 kb        2.247       40  TauPi0Clusters (DataVector<xAOD::CaloCluster_v1>) [tau]
     373.886 kb      144.574 kb        3.614 kb        2.586       40  TauPi0Clusters_links (CaloClusterCellLinkContainer_p1) [tau]
     559.632 kb      229.120 kb        5.728 kb        2.443       40  CaloCalTopoClusters_links (CaloClusterCellLinkContainer_p1) [CaloTopo]
     649.238 kb      245.023 kb        6.126 kb        2.650       40  CaloCalTopoClusters (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
     518.233 kb      121.040 kb        3.026 kb        4.282       40  TauJets (DataVector<xAOD::TauJet_v3>) [tau]
```

q221 with timing cut:
```
     268.669 kb      119.530 kb        2.988 kb        2.248       40  TauPi0Clusters (DataVector<xAOD::CaloCluster_v1>) [tau]
     373.382 kb      144.688 kb        3.617 kb        2.581       40  TauPi0Clusters_links (CaloClusterCellLinkContainer_p1) [tau]
     558.644 kb      228.493 kb        5.712 kb        2.445       40  CaloCalTopoClusters_links (CaloClusterCellLinkContainer_p1) [CaloTopo]
     643.752 kb      242.926 kb        6.073 kb        2.650       40  CaloCalTopoClusters (DataVector<xAOD::CaloCluster_v1>) [CaloTopo]
     517.741 kb      120.767 kb        3.019 kb        4.287       40  TauJets (DataVector<xAOD::TauJet_v3>) [tau]
```

Too early to tell whether this is beneficial for taus :-), this will require in-depth studies based on true tau MC (gamma*->tautau and LLP->tau).

Cheers,
Bertrand