Consider file pfn vs lfn in schemas

thanks to some debugging, I notice that data in /project/monitoring/archive/xrootd does not contain lfns, but rather some mix of pfn and lfn. (presumably whatever name the user used to open the file). My guess is that this is more widespread than just this one monitoring source. Consider updating schema column names to reflect this to improved readability.

Start by locating the schema definitions used for /project/monitoring/archive/xrootd and checking whether its values are PFNs, LFNs, or both. Compare other monitoring sources before deciding whether column names should change; done means the schema names accurately describe the data across the affected sources.

Written by the indexing model from the issue text.