Delete seasons workflow refinement

[sitarane]

Users should be able to delete a season if they created one by mistake. There should be a countdown of, IDK, 10 minutes, where it's possible to delete a season you created, as long as it doesn't get positive vouches. The delete button is in the flash message, and is called "undo".

Do not allow people to post a new season and later delete it as it games the system.

Add a "Are you sure this season is correct. Seasons can only be deleted by getting enough downvotes, which would affect your score in a bad way".

(Do not allow to edit a season)

NB: we don't need jobs for this. Just check creation date before deleting.