Mirador 3: please add t.o.c. display to the image viewer

Using page title data if it exists, display a t.o.c. for an item.

It looks like this is the index. (see GSU embed example, https://dlg-staging.galib.uga.edu/record/gsu_lane_8939)

Associate the page title data with the navigation thumbs

https://dlg-staging.galib.uga.edu/record/dlg_sanb_thomasville-1920 has page-level titles.