Hides Quiz icons in gradebook/grade summary until DB is ready

The quiz icons are hidden away until the appropriate features are out to
allow for monitoring of gradebook/speedgrader edits to quiz scores which
are pending review because of their question types.

Closes CNVS-16399

Change-Id: I689f1dcc94a647a32fe619b215f6b641a8376f84
Reviewed-on: https://gerrit.instructure.com/43180
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Derek DeVries <ddevries@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Ryan Taylor <rtaylor@instructure.com>