Add optional ML based e/p workflow

This adds an optional workflow, not to be used in production, that predicts the e/p for a track using a ML model. The main changes are the addition of a new tool, PFEnergyPredictorTool written by @abarton , along with associated toggles to enable usage of this via a python flag. I tested on 2000 ttbar events that the output looks the same with physics validation. RunWorkFlowTests_run3.py indicated no frozen violating tier0 changes. The above is as expected, given this workflow is not enabled by default.

Reconstruction/eflowRec/src/PFEnergyPredictorTool.cxx

@@ -150,11 +150,6 @@ float PFEnergyPredictorTool::nnEnergyPrediction(const eflowRecTrack *ptr) const{
      std::vector<eflowRecCluster*> matchedClusters;
      std::vector<eflowTrackClusterLink*> links = ptr->getClusterMatches();
 
-     std::stringstream phi;
-     std::stringstream eta;
-     std::stringstream clustphi;
-     std::stringstream clusteta;
-
     std::array<double, 19> etatotal = getEtaTrackCalo(ptr->getTrackCaloPoints());
     std::array<double, 19> phitotal = getPhiTrackCalo(ptr->getTrackCaloPoints());
 
@@ -183,15 +178,8 @@ float PFEnergyPredictorTool::nnEnergyPrediction(const eflowRecTrack *ptr) const{
         totalE += clusterE;
 
         matchedClusters.push_back(clink->getCluster());
-        phi << clink->getCluster()->getCluster()->phi();
-        phi << ',';
-        eta << clink->getCluster()->getCluster()->eta();
-        eta << ',';
      }
 
-     phi << links.size();
-     eta << links.size();
-
      std::vector<std::array<double, 5>> cells;
 
     const eflowTrackCaloPoints& trackCaloPoints = ptr->getTrackCaloPoints();
@@ -228,10 +216,6 @@ float PFEnergyPredictorTool::nnEnergyPrediction(const eflowRecTrack *ptr) const{
            auto theDDE=it_cell->caloDDE();
            double cx=theDDE->x();
            double cy=theDDE->y();
-           clustphi << theDDE->phi();
-           clustphi << ',';
-           clusteta << theDDE->eta();
-           clusteta << ',';
 
            cells.emplace_back( std::array<double, 5> { cellE,
                     theDDE->eta() -  eta_ctr,