Possibility to add custom correlations using names of Q-vectors

New function in global config, making possinble to get config with name of qvector New function on correlation task to add custom correlation via names

src/base/GlobalConfig.h

@@ -34,6 +34,19 @@ class GlobalConfig : public TObject {
 
   const std::vector <Qn::QvectorTracksConfig>& GetQvectorsConfig() const { return track_qvectors_; }
   const std::vector <QvectorChannelsConfig>& GetChannelConfig() const { return channel_qvectors_; }
+  const QvectorConfig& GetQvectorConfig( const std::string& name ){
+    for( const auto& vector : track_qvectors_ ){
+      if( vector.GetName() == name )
+        return vector;
+    }
+    for( const auto& vector : channel_qvectors_ ){
+      if( vector.GetName() == name )
+        return vector;
+    }
+    std::cout << "Error in GlobalConfig::GetQvectorConfig" << std::endl;
+    std::cout << "No such Qvector named " << name << std::endl;
+    abort();
+  }
   const QvectorConfig& GetPsiQvector() const {return psi_qvector_;}
   const std::vector <Qn::AxisD>& GetCorrectionAxes() const { return correction_axes_; }