for TNL-6594

Add a new waffle switch that allows us to assume zero grades for
learners who have no entry previously recorded, and another to
disable persisting grades for unengaged learners.

TNL-6691

for TNL-6644

* Bump xblock version
* Update rescore instructor task helper to handle generic rescore.
* Add set_score to grade signal handler.

Some old mongo courses do not have this field, and the team has opted
to allow null values rather than inserting a default. This change
affects both course and subsection grades.

TNL-6408

As discovered in load testing, if this task is run too quickly it
can ask for a newly-recorded score prior to the active transaction
finishing and writing to the database.

TNL-6424

TNL-6331

TNL-6250

Also fixes issue where ORA grades were never updated, by including
them in this check.

TNL-5994
TNL-5995

for TNL-5045

Remove deprecated SingleSectionGrader.  TNL-5987
Remove display_name and module_id from Scores objects
Update CourseGradeFactory.__init__ to not be user-specific
Update some callers to use CourseGrade class instead of "summary" dict
Remove no longer needed course_grades.py module.
Renamed django signal from GRADES_UPDATED to COURSE_GRADE_CHANGED

For TNL-5993

TNL-5817

TNL-5909

Update course grade query parameters and check scores when updating subsection grade

For TNL-5861

Makes use of the new SUBSECTION_SCORE_CHANGED signal to trigger a task that
updates persisted course grade values. We've also renamed SCORE_CHANGED to
PROBLEM_SCORE_CHANGED to head off any issues with unclear signal names.

TNL-5740

TNL-5046

For better user-facing performance, the SCORE_CHANGED signal is now handled by
enqueueing an async task to update the relevant stored grade, rather than
making the request wait until that operation finishes.

TNL-5738

This reverts commit 31812141.

TNL-5062

TNL-5458
TNL-5493

* First take at forcing a subsection's grade to update when a signal is
  sent that a problem's score has changed
* Refactor signal handler connection.
* Expand bokchoy tests to cover progress page
* Add some grading unit tests

TNL-5394
TNL-5364