build ember moderate table with student data

closes CNVS-12572

test plan:
  - enable ember quizzes
  - as instructor go to moderate tab
    - verify that student data is populated in table
    - verify that checkboxes can be selected
    - verify that table includes students with no submissions

  - as student take a quiz
    - visit ember quiz show
    - verify that user cannot change inputs (radio buttons) in
      submission html at bottom of page

Change-Id: I79d5f4eacfe8e4a56f7036846c3291da9bf1f6a5
Reviewed-on: https://gerrit.instructure.com/34368
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ahmad Amireh <ahmad@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Jason Madsen <jmadsen@instructure.com>