Cleanup HGTD and InDet GeoModelXml detector tools
This one is a bit big, but as all changes are the same, I did it all in one go:
- cleanup CMake dependencies of HGTD and InDet GeoModelXml packages
- unify how the geometries are built
- add a helper to check if the description exists in geometry database
- allow reading future geometry tags
/cc @nstyles @dfellers @janovak @dshope @aleopold @sridouan @tsulaia