Reminders for untaken surveys

[jaytoday]

For the midterms, the administrators would like to be able to send notifications to users who have not yet taken surveys. This would most likely be in the form of a button on the create/edit page.

The existing notification code could likely be used for this feature.

[ajaksu]

POC added in a1e77d3, I'll have to read some new code to figure out how to support this properly.

[jaytoday]

These reminders can be determined (both for Mentors and Students) by iterating through projects and looking for a SurveyRecord with the appropriate reference.

If a student has not taken the survey, both the student and mentor should be reminded. If the mentor has not taken the survey, the mentor (and the org admin?) should be reminded.