Base implementation for eft lines in likelihood plots.
With testing config in /afs/cern.ch/work/t/tolange/inference_master/inference/plots/eftlines.dat (use --eftlines FILEPATH in PlotLikelihoodScan (2D only))
With testing config in /afs/cern.ch/work/t/tolange/inference_master/inference/plots/eftlines.dat (use --eftlines FILEPATH in PlotLikelihoodScan (2D only))