update API doc required params - 8

- Notification preferences
- Outcome groups
- Outcome results
- Outcomes
- Pages

Test plan:
- rake doc:api
- Verify the above doc pages for parameter accuracy

Refs SIS-403

Change-Id: I98fd1370902bb7570d75713b569a3b0779bf408a
Reviewed-on: https://gerrit.instructure.com/39311
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Duane Johnson <duane@instructure.com>
Product-Review: Duane Johnson <duane@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>