Design & implement uploading end-of-seasons events

At the end of the year, TOs will have until 31.10 to upload results that account toward the qualification for the 2023 invitational. We should design a way for them to be 1) notified that this is the case, and that their event could not be processed, but also 2) offer them a way to upload results that count toward the 2024 season if they wish to.