Condense download graded paper buttons

[srisainachuri]

LGTM. Not tested on stage.

Lots of reused code segments makes me think we can shove some parts of this into a react component on its own and pass the paper object and graded_files[paper.id] into the component.

Also I wonder what JS code convention is between the repeated gradedHrefData ? and a giant if {} block.

Originally posted by @erwang01 in #803 (review)

[srisainachuri]

Main Code pointers:
PaperGradeTable.js
PaperSubmissionTable.js
AdvisorPaperView.js

Condense the Download Paper menus in all of these into a single component.