Create simple nested helpers that attempt to classify an opinion as "Syllabus" or "Per Curiam"

[JCRascal]

Current state of helpers at closing of this ticket:

1. Check if document is "Syllabus"
2. Check if document is "Per Curiam"
3. Various checks (development in progress) for author name

If any step finds what it is looking for, the search stops and the value is returned.

In the future, consider refactoring to reduce the number of required functions. Named author checks will be tracked by a separate ticket