Bulk assign roles in course categories when using Upload users

To test with the sample test file:

1. Create MGMT category:
   1. Go to Site administration > Courses tab > Add a category. Set category name and id number to be 'MGMT', then click "Create category".
2. Create course management1 under MGMT category:
   1. Go to Site administration > Courses tab >Add a new course. Enter course full name and course short name as management1. Then click "save and display".
3. Upload users:
   1. Go to Site administration > Users tab > Upload users. Drop upload_users.csv to the file upload area and click "Upload users".
   2. In Upload users preview, see that users here have category MGMT and categoryrole management.
   3. Click "Upload users", verify that no error message is logged through Enrollment column. Verify that at the bottom of the page, it says "Users created: 2 Users skipped: 0 Errors: 0". Click "Continue".
4. Verify category role:
   1. Go to Site administration > Courses tab > Manage courses and categories. Go to category MGMT > Assign roles (small gear next to it), verify that there are 2 users with role 'manager' and their other information match with upload_users.csv.
5. Verify course role:
   1. Go to the course page for management1, click on Participant, verify that there are 2 users with role 'student'(category role) and 'manager'(specific course role) and their other information match with upload_users.csv.