Reorder queue

Reorders the first queued posts of the channel. Send the ids of the first N queued posts (scheduled in queue mode, more than a minute away, in time order) in the new order: the posts swap among the times they already hold, and the posts after the first N stay where they are. When the ids are not exactly those first N posts (the queue changed), the request returns 422 on post_ids. Custom-time posts are not part of the queue.