Updating the beam hole in PrHybridSeeding

The PrHybridSeeding has a possibility (True by default) to remove by hand the beam hole in the search for (u,v) hits. This cut was implemented when that hole was circular, but it has now been changed. This MR proposes new options to change the beam hole size and shape. Still to do: take into account the tilt angle in the (u,v) stations. After discussion with @rquaglia, the RemoveHole has been left to True by default.