Remove confidence ratings from instructor interface

[Kim Jones Davenport]

Per Andy, this is a big priority. Only researchers should have permission to see student ratings, regardless of whether an experiment is happening. We would also like to communicate to students that confidence ratings are not shared with the instructor, are used by OST to gauge their progress and to identify future learning activities that will help them achieve their goals.

This will entail removing the confidence ratings from the grading interface and instructor research report. Researchers should be able to view confidence ratings in the research report; not necessary to include them in the researcher interface.