[Gradebook] allow rubric grading in the gradebook menu

[ShawnaFailner]

Problem statement:

In order to use a rubric for grading, one must go to speedgrader to enter in rubric options. That requires more clicking by teachers. Currently teachers can insert a grade, but cannot use the rubric to grade from this page.

Proposed solution:

Allow a rubric grading on the gradebook page (where you can enter grades in the pop-up window on the right when clicking on the expand button), instead of requiring teachers to click on speedgrader to insert a rubric grade.

User role(s):

admin,instructor