(Exhibition Config UI for end users)

Add an exhibition visibility link to the exhibition configuration page.

This link will open a new window that allows visibility settings to be changed. Refer to this document on how to structure the UI:
https://confluence.si.edu/display/SIDDEV/Exhibition+Visibility

When the user saves the information, serialize the information and store it in the exhibition_config table in the visibility column. Create a function to retrieve that information with the pid as a parameter and the visibility object tree as the return.

A pid may occur multiple times in the tree and have different visibility settings for each appearance. (For example a resource is under 2 different concepts.) If there is a loop, do not allow the loop to be shown: If a concept has one of its full path of parents as a child, do not attempt to show that child.