This MR completely re-designs the track extrapolation code used for FastCaloSim and addresses the issues described in ATLASSIM-3874. The main method extrapolateToCylinder aims to find the best position on any cylinder surface defined by its radius and half-length starting from a vector of hit positions. First, extrapolateWithIntersection will try to find (forward) intersections between the cylinder and the infinite lines generated by the subsequent combination of the hit positions. If no good intersection is found, extrapolateWithPCA will use the Point of Closest Approach (PCA) of the polygon spanned by the individual line segments on the cylinder as extrapolated position. More information on how the new extrapolator works as well as a summary of the validation is documented in ATLASSIM-4805.