[User Story] Provide a way to delete all poll history at once

[jody]

Story

As an instructor,
I want to delete all poll history data at once,
So that I can have a clean workspace for future polling.

Acceptance Criteria

This criterion would satisfy the "I want" but might not be the best solution for the "So that":

• Instructor can delete all poll history data in a single action, subject to confirmation

Thoughts

• This is a destructive action that warrants signficant thought and good usability design.
• Consider providing ways to archive and restore all poll histories, such as a batch CSV download to mitigate the irreversibility.
• Consider providing a way to "hide" poll histories, so that they don't need to be deleted to have the desired clean workspace.