[devel] [WIP] Fix determination and usage of platform from config + scripts minor changes

• Add new utility in Core.Utilities.ProductionEnvironment to get the CMTCONFIG values compatible with the current machine from the /Operations/PlatformsToConfigs section and no longer from /Resources (i.e. no longer use getDIRACPlatform)
• Modify dirac-architecture to use the above
• Modify JobDB.py to use the above

Few scripts improvements

• Add information to result if no ancestor is found (fixes https://its.cern.ch/jira/browse/LHCBDIRAC-735)
• Add switch --Files to list-directory in order to not list the subdirectories