Course Grade reports: eliminate CSM calls, user-transformed structures

common/lib/xmodule/xmodule/graders.py

lms/djangoapps/grades/context.py

lms/djangoapps/grades/course_data.py

lms/djangoapps/grades/course_grade.py

lms/djangoapps/grades/course_grade_factory.py

lms/djangoapps/grades/subsection_grade.py

lms/djangoapps/grades/subsection_grade_factory.py

lms/djangoapps/grades/tests/base.py

lms/djangoapps/grades/tests/test_course_grade_factory.py

lms/djangoapps/grades/tests/test_subsection_grade.py

lms/djangoapps/grades/tests/test_tasks.py

lms/djangoapps/instructor_analytics/basic.py

lms/djangoapps/instructor_task/tasks_helper/grades.py

lms/djangoapps/instructor_task/tests/test_tasks_helper.py