Overexposed API in geolocate_oci.h

Many functions declared in geolocate_oci.h are only used in geolocate_oci.cpp, so the declarations should be moved there. This will require a reshuffle of the code in the source file. The work on this ticket should mostly consist of moving code or deleting code, not new code. And exception to this may be expandEnvVar, which probably doesn't need to exist.