add student extension dialogs on new ember quiz moderate page

fixes CNVS-12449

test plan:
  - as a teacher
  - enable fabulous quizzes
  - enroll a few students in the course

  - there is a new quizzes api attribute called 'quiz_extensions_url'
  - check out the jsonapi quizzes api to make sure this attribute only shows
    up for teachers (and not students)

  - create a quiz with no time limit and unlimited attempts
    - visit the quiz moderate page
    - click the "edit" icon for a student
    - the modal dialog should only allow you to "manually unlock"

  - create a quiz with a time limit
    - visit the quiz moderate page
    - click the "edit" icon for a student
    - the modal dialog should only allow you to "manually unlock"
    - the modal dialog should only allow you to add "extra time"

  - create a quiz with a limited number of attempts (1 or more)
    - visit the quiz moderate page
    - click the "edit" icon for a student
    - the modal dialog should only allow you to "manually unlock"
    - the modal dialog should only allow you to add "extra attempts"

  - create a quiz with both a time limit and a limited number of attempts
    - visit the quiz moderate page
    - click the "edit" icon for a student
    - the modal dialog should only allow you to "manually unlock"
    - the modal dialog should only allow you to add "extra attempts"
    - the modal dialog should only allow you to add "extra time"
    - change the settings for extra attempts, extra time, and manually unlock
    - hit submit
    - it should save these new settings if you reopen the dialog
    - it should show the extra minutes allowed on the attempt under the username
    - it should add the extra attempts to the 'attempts left' column value

Change-Id: I0e10942ff7a3a80cec200468216ba0641decee2c
Reviewed-on: https://gerrit.instructure.com/35089
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Reviewed-by: Ahmad Amireh <ahmad@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>