There is no way to embed that with the workbook itself (at least in any meaningful way -- a packaged workbook is really just a zip file, so maybe you could include other files inside the zip -- I haven't tried it and I can't think of how that would be practical for the end user).
A couple of options come to mind:
1. Embed a web page in a dashboard that hosted the documents or provided links to the documents.
2. Have a URL action that linked directly to the documents.
Would either of those two be feasible?
I like the URL option. I think we have google docs available so I can just reference that.
Like Joshua said, the URL link works great.
If you wish to store the file on the Tableau Server instead of some other host see here: http://kb.tableausoftware.com/articles/knowledgebase/accessing-web-server-tableau-server
It doesn't provide any security natively, but that probably wouldn't be a concern for a FAQ. Might be cleaner to store there. Just a thought.