Draft: Common DetectorTool for all GeoModelXml-based geometries

...as above. Try to make a generic base class to avoid duplication of code across different systems, plus some clean-up, and new functionality.

Implementing use of this first for StripDetectorTool as an example, to get feedback before using it also for Pixel/HGTD/PLR, etc...

The DetectorTool now does the job of the DetectorFactory too, to avoid awkward passing on of Athena services and properties that was previously necessary. Dependence on AthenaBaseComps is removed, as are StripOptions.

Moving ITkStrip first, all other GeoModeXml-based geometries should then follow this pattern too, to be able to make use of the common base class.