update page titles in ember quizzes

update the document.title to be consistent with the page that the user
is viewing. update existing moderate page title to be consistent

closes CNVS-12974

test plan:
  - enable :quiz_stats feature
  - enable :quiz_moderate feature
  - visit quiz index
    - title should display 'Quizzes'
  - select a quiz
    - title should display '<quiz title>: Overview'
  - select the moderate tab
    - title should display '<quiz title>: Moderate'
  - select the statistics tab
    - title should display '<quiz title>: Statistics'

Change-Id: I36d94014e2225d78d59d35c77b16bb82af48d644
Reviewed-on: https://gerrit.instructure.com/36016
Reviewed-by: Derek DeVries <ddevries@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Jason Madsen <jmadsen@instructure.com>