User can view the change in number of enrollees enrolled in the past week (default)

[crathbun428]

User Story
As a course author, I want to view the change in the number of enrollees in my course over the past week, so that I can view recent enrollment activity at a glance from the course dashboard.

Acceptance Criteria
Scenario: A course author can view the change in enrollment over the past week from the course dashboard
Given I am a course author with X permissions
When I look at the change in enrollment information in the enrollment section of the course dashboard
Then I can see the number of enrollees who enrolled in the course over the past week

[SoryRawyer]

I think this can be charted using the fact_enrollments_by_day dataset in Superset.