Add functionality for DetectorType to ITk Strips

In ReadoutGeometryBase, we define a DetectorType enum, giving details about the detector region. This is already in use for the ITkPixel, HGTD and PLR, but not ITkStrip since the information provided can easily be retrieved from the Identifier already. However, in the interests of consistency across the Phase 2 detectors, this is added here for ITkStrip too.

Currently this will trigger a WARNING if detector description files try to set the type to anything but what would be expected from the code path, but in future if more fine distinctions are to be added to the DetectorType, the checks which currently trigger a WARNING message could be relaxed/removed.

FYI @sroe