Scheduled Events

Relays implementing this behavior should accept events dated in the future, but keep them stored in a different bucket so that they aren't revealed to any readers.

Then, when the time comes for such events to be published, i.e. their created_at timestamp arrives, they should be moved to the main relay storage bucket and made readable.

They should also, at that same time, be broadcasted to any active listeners that would have filtered for them.

Relays should signal support for this feature by using the (old, deprecated) number 16 in their supported_nips array of their NIP-11 response.