Configuration option for public folder visibility

[mark-dce]

STORY
As a blacklight implementer, I would like to be able to choose whether users need to be logged in to view 'public' user folders, so that I can control whether the general public can see folders or only my institution's users.

DETAILS
Consider a case of a reading list for a course saved as a folder and set for public visibility:
Case 1) It's possible that the institution's policy may be to make all of this type of information public access, in which case unauthenticated users should be able to access a list that's been made public.
Case 2) The institutions may consider reading lists part of the institutional assets that students pay tuition to gain access to, in which case only authenticated users should be able to access a list that's been made 'public'

ACCEPTANCE

• There is a configuration option that allows the implementer to easily control whether 'public' folders can be viewed by unauthenticated users OR only by authenticated users.
• The blacklight-folders generator sets this option to allow access by unauthenticated users as the default
• The setting is documented in the gem's wiki