fm_IDL.xml needs cleanup

I've noticed for years now that the lack of reports labels for fields in the IDL file contribute to confusion/frustration around using reports in Evergreen, but I was editing the fm_IDL.xml file recently and noticed that it has accumulated a lot of cruft and needs auditing and if nothing else, some formatting/whitespace cleanup and some overall organization. Pretty sure this isn't a high priority but it's kind of like the closet we keep shoving clothes into that will eventually become unmanageable.