Comprehensive packaging improvements
    
    - Switch to pyproject-rpm-macros (“new guidelines”)
    - Do not distribute questionably-licensed sample PDFs, and skip the
      tests that require them
    - Build PDF documentation in a new -doc subpackage (instead of simply
      distributing the documentation sources)
    - Correct License field from “MIT” to “MIT and Public Domain and APAFML”
    - Add downstream man pages for command-line tools
    - Switch cmap-resources BR to adobe-mappings-cmap