Read Material map for Acts Fatras from calibration area using PathResolver (ATLASSIM-5948)

We need to be able to pick up the material maps from cvmfs to be able to run Acts Fatras in Athena on the grid (ATLASSIM-5948).

The first two commits are just tidying the legacy configuration and could go in separately.

The third commit does the actual change. The PathResolver determines the path correctly, but then we still seem to get the same error as in ATLASSIM-5948:

ActsTrackingGeo...   INFO Configured to use material input: /cvmfs/atlas.cern.ch/repo/sw/database/GroupData/ACTS/material-maps-ATLAS-R2-2016-00-00-00_v1.json
ActsTrackingGeo...  FATAL in sysInitialize(): standard std::exception is caught
ActsTrackingGeo...  ERROR Unable to open input JSON material file
ServiceManager      ERROR Unable to initialize service "ActsTrackingGeometrySvc"

It seems to be a permissions issue with the cvmfs directory still, as if I copy that file locally and PathResolver finds it OK and the job runs (it generates fails for other reasons later). Will follow up on ATLINFR-4621, but it would make debugging easier if this change goes in.

Tagging @rwang, @lmijovic, @asalzbur, @pagessin, @tlari