speedgrader: move gobbledygook into handlebars template

Test plan:
  use speedgrader to:
  * go to a student that has multiple submissions.  the submissions
    drop down should exist and work (for assignments and quizzes)
  * go to a student that only has one submission.  the dropdown should
    not be there
  * go to a student that has no submissions.  it should look OK.

Change-Id: I066f574ac477adcc6f2bd88012e5ae5966726230
Reviewed-on: https://gerrit.instructure.com/33242
Reviewed-by: Simon Williams <simon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>