Fixes for running LAr G4 simulation over persistent GeoModel description

Implemented patches to several LAr packages, and also to Geo2G4, in order to
allow running LAr G4 simulation when GeoModel description is read from
SQLite database. The patches are mostly required for finding proper
implementation of the IRDBAccessSvc interface at run time.

The changes are not expected to affect the current default method of
building GeoModel, i.e. reading from the Geometry DB.