Implement max-view

The Gist: The first view you hit during your GALILEO session, no matter how you got in, eg a link to a specific view provided by a teacher, or via the wayfinder, that becomes your “max view” during that session.  E.g. if you click middle school, you won’t be able to go “up” to High School, but you’ll be able to go “down” to elementary school.