[#69564154] Status codes and reminder template
[#69564154] Add reminder mailer spec

Add spec to verify that reminders have sent
[#69564154] Refactor reminder popover dom

Remove custom region and positioning.
Make event position relative.
Place reminder popup as an absolutely positioned element.
[#69564154] Add media query for event reminder

Render event reminder along the side of the page when the screen gets
very small.

Reorganize stylesheet to group reminder styles together.