Add closed state

# Changes
 - Adds an 'enable voting' boolean setting, defaulted to true. When set to false, it hides vote buttons and voting form, and disables vote & user login routes.

Closes #255.
Based on whether or not winners are being shown, we should have different text for the non-winner drawers. So if `$settings['show_winners']` or whatever, then it would not make sense to say "We'll post the winners soon!"