get rid of fabulous quizzes route/action so that url is just /quizzes

fixes CNVS-13375

test plan:
  - turn on fabulous quizzes
  - we should no longer see 'fabulous_quizzes' in the url as we navigate around
  - redirection from quizzes/{id} should still work correctly
  - redirection from quizzes/{id}/modreate should still work correctly
  - redirection from quizzes/{id}/statistics should still work correctly
  - visiting a url directly without being logged in should prompt to login

Change-Id: Ib8c4eaacbc098c7168c27a93d16e9443f25bbbca
Reviewed-on: https://gerrit.instructure.com/35723
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ahmad Amireh <ahmad@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>