ActsTrackFinding: simplify filling of helper objects

• TrackingSurfaceHelper vector can now be filled element-by-element. This simplifies (and maybe slightly speeds up) its use in CoreStripSpacePointFormationTool, ProtoTrackCreationAndFitAlg, and TrackFindingAlg.
• TrackFindingMeasurements::addDetectorElements() call doesn't need the whole clusterContainer, just the measurement type.
• Remove gatherGeoIds(), moving functionality into TrackFindingMeasurements::addDetectorElements
• Improve MeasurementRangeList API
• Avoid taking reference to temporary object when constructing CkfBranchStopper. This was only used by TrackStatePrinter.
• Rationalise some names in TrackFindingMeasurements: m_measurementOffset → m_measurementOffsets, measurementOffsets() → measurementContainerOffsets(), and measurementOffsetVector() → measurementOffsets().