upgrade list_forum_members api to DRF

[awais786]

verify via postman

1: Try this URL with post request.
post-data = rolename: Group Moderator or any other role.

2: Valid data should be existed in admin/django_comment_common/role/ table.

expected result
{ "course_id": "course-v1:edx+cs222+2311", "Group Moderator": [ { "username": "login_service_user", "email": "[email protected]", "first_name": "", "last_name": "", "group_name": null } ], "division_scheme": "none" }

[kdmccormick]

@awais786 can you add to DRF to the issue titles so they make sense in the issue list?

[awais786]

@awais786 can you add to DRF to the issue titles so they make sense in the issue list?

All titles updated.