Refactor code to read GeoDB
Move detector-specific code to read the geometry database into
standalone "[Det]GeoDB.py" modules. Use this code both in the old
jobproperties as well as in the new-style AutoConfigFlags to avoid the
copy&paste of the same code.
Also fix the caching of AutoConfigFlags.GetDetDescrInfo to make sure the
geometry DB is only queried once per geometry tag. The latter was not working and
was responsible for glacially slow job configurations for certain jobs (e.g. trigger).
Likely further re-factoring will be done in a follow-up MR that will also require changes in clients to avoid possibly clashes of detector descriptions flags across systems.