[FIX] Ticket#5534. Using wkhtml2pdf to generate PDFs from wikipages even they are restricted (so only visible to certain users). Uses the feature "auth_token_access". "auth_token_access" is not required if the page to be exported to pdf is visible to anonymous users. Updated the pref file to require this feature if pdf export is to be enabled. Note: wiki pages that have a trackerinput still fail bc of access problems. This might be based on how the token mechanism is implemented.