Jrbl/substitute anonymous user id in html

Co-authored-by: Nate Hardison <natehardison@gmail.com>

@natehardison and @jbau 

Code works end-to-end with qualtrics; I'm just tagging you guys to be certain I'm pulling into the right place.

This doesn't do a per-course secret and it doesn't generate a new unique hash per user, but today I was told this would be sufficient for our one course that needs this, for the time being. I can't afford to spend any more time on doing it right at the moment, so we'd like to pull this in and move on, and circle back around to building a general mechanism for anonymization later in the Summer.