Visual enhancements and role permissions

--DCP-437: Updated sidebar link colors for About Pages and Feature
Pages.
--DCP-452: CURIOSity: Move Items page link from Curation area to
Configuration area
--DCP-453: CURIOSity: Move Tags page link from Curation area to
Configuration area
--DCP-436: CURIOSity: Enable 'curator' role to add thumbnails to browse
categories and pages
--DCP-471: CURIOSity: Allow site admin users to toggle between site
admin and curator roles for testing purposes
--DCP-376: CURIOSity: DESIGN - Masthead no longer reflects crop and
distorts the image
--DCP-478: CURIOSity - Update footer link

2.3.2-lts-5

--Using Google Fonts locally and disabled turbolinks on homepage Visit Exhibit links. to allow CSS to fully load (DCP-372)
--Removed extra menu that appeared to right of screen (DCP-379)
--Updated footer links (DCP-381)
--Corrected sort order when faceting (DCP-184)