New way to find the point on hit segment closest to the nearest wire

sTGC time response is parametrized in terms of the distance of smallest approach. So digit time indicates to some accuracy the distance between the wire and the hit. The position where this distance intersects the wire is the position charge is induced on the wire, strip and pad channels. Since the sTGC channels are staggered, it is important to determine this position correctly. Then combining the measurements of all layers would improve the resolution. This merge request introduces a new method to compute the smallest distance between the hit and wire, and determine the two points (on the hit segment and on the wire) where distance is smallest.