Lima/vecgeom 206 - new tube kernel SafetyKernel()
Combined tube's SafetyToIn() and SafetyToOut() into SafetyKernel(), reducing code duplication.
I am suggesting similar SafetyKernel()'s for all other shapes. The SafetyToIn() and SafetyToOut() can probably be promoted to ShapeImplementationHelper.
Comments/suggestions are welcome.