CQS: FIMB and friends

This patch adds question statistics for Fill In Multiple Blanks,
Matching, and Multiple Dropdown question types to the CQS client app.

Closes CNVS-15215

TEST PLAN
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  - create a quiz with the question types above as well as the old ones
    (MC, T/F, FITB and friends)
  - take it by a number of students and generate stats
  - go to statistics cqs page
  - verify all those question types render
  - verify the new ones render with tabs for each "answer set" (e.g,
    blank)
  - click the tabs, verify that:
    + answer drilldown section updates with the answers for that set
    + correct answer donut chart and the message update
    + answer distribution bar chart updates

Change-Id: Ia554832a5825cdb4b883e3db6fd4b3c75dd2599e
Reviewed-on: https://gerrit.instructure.com/40543
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Derek DeVries <ddevries@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>