paginate enrollments by loading them through the api. load
new pages by clicking 'View More Enrollments' link.
affects: sections controller
test plan:
* create course with large number of students (~ 500);
* visit course section page (/courses/:course_id/sections/:id);
* verify that page loads first 15 of both current and completed
enrollments;
* verify that if no enrollments exist in a category, a 'no enrollments
found' message is displayed;
* verify that clicking 'Load More Enrollments' loads another page
of enrollments;
* load a course with < 15 enrollments, verify that no 'View More
Enrollments' link is displayed.
Change-Id: Ied7ccdd8e59a56bef44ffbb07292ecfc0cb97ec5
Reviewed-on: https://gerrit.instructure.com/8365
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>