Minor content revisions, more xrefs replace URLs, drop statscache
    
    This commit makes minor content revisions and corrections, moves more
    cross-document linking from hard-coded URLs to internal Antora anchors,
    and removes statscache from the CommOps toolbox, since it is likely to
    go away in the near future.
    
    Actual changes to source content were kept minimal, other than a slight
    modernization to current times. More unique content change will come in
    later PRs.