show success notification on course settings form submit

test plan:
* submit the course settings form
* should reload and show a notification on successful save

closes #CNVS-17001

Change-Id: I84d4bb52116724ee0d597550149c649f14af7bb6
Reviewed-on: https://gerrit.instructure.com/44627
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Jahnavi Yetukuri <jyetukuri@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>