Add poll closing

[cletusc]

• [x] Polls should be automatically closed after 30 days.
• [x] Poll creators should be able to manually close.

[cletusc]

This will require adding a creator field on the poll, which should populate the creator info. Once that happens, a close button can be displayed and we can actually check if they are the creator.

This will also require a closeTime field which should default to Date.now() + 30 days and otherwise be what the creator chooses. Validation should be done to prevent it exceeding 30 days after create time.

Can check if a poll needs to be removed by checking if closeTime + 2 weeks < Date.now().

This would not allow an anonymous creator to manually close after creation, but can schedule a close during creation.