move quiz_submission views to quizzes directory to match namespace change

Change-Id: Ieb0fea60a1ea55d3499356014553b4fb274b8a70
Reviewed-on: https://gerrit.instructure.com/32266
Reviewed-by: Josh Simpson <jsimpson@instructure.com>
Reviewed-by: Brian Palmer <brianp@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>
Tested-by: Bryan Madsen <bryan@instructure.com>