Add course statistics

[zhuhanming]

Summary

Adds the new course statistics components to the statistics modules, namely:

• Chart on student progression
• Table on student performance (with more metrics beyond gamification metrics and video statistics)
• Table on student statistics

Closes #619 and #1112 (after a few more minor changes).

TODO

• Show in UI which submissions are late/overdue
• Add groups filtering (and perhaps support group average vs class average comparisons)
• Possible extension would be Student Watchlist #113, since now we can check specific rows in the table and perform operations. Instructors should be able to select these students and add them into the watchlist.
• Write more tests, especially on the correctness of the statistics provided.

Will add screenshots to this PR later.

[zhuhanming]

Mostly superseded by #5440.