Add config for ITk separate from InnerDetector

Adding new configuration blocks and modules to allow ITk configuration to be separated as far as possible from that of the current detector.

Also fix some issues in StripGeoModelXml that were noticed during tests. Specifically:

• the map of pointers to DetectorDesigns had to be replaced, since the use of unique_ptr and std::move semantics meant that this map was actually empty when it came to be used. Replaced with a map storing an index that can be used to retrieve the correct design via the DetectorManager
• Correctly initialize a member related to the DB access

So far, this will allow the ITk strip to be built and a simulation example based on the new ComponentAccumulator to run successfully. Doesn't yet create any HITS output since the Sensitive Detectors are not yet declared. That will come in the next step in a separate MR.