Change match computing and notification functionality

[MJDeligan]

The current idea is:

• The event ends
• The organizer sets a delay
• Matches are computed
• User's are notified after the delay

The problem is that users would be able to see matches before the delay, because we are only delaying the messaging and not the computing. This would require more tables and cron jobs to orchestrate.

Instead we will have organizers manually compute and publish the results, so we will need to:

• Remove the delay set on events
• Add a function that computes matches and then sends the notifications via edge functions
• Add the required UI and logic to the frontend for organizers after they end the event
• Remind organizers if they haven't published the results after some time

We probably won't use the notifications table for this anymore, because we create and then immediately send and discard the notifications, so we might as well just use a temp table.

Maybe we should add some indicator to events whether the results have been published or not, so that users aren't confused about whether they should be seeing their matches for an event or not.

To remind organizers we could add an end timestamp to events, which is computed when the event is actually ended. That way we know how much time has passed, since the end of the event and can show a reminder in the app after X hours or have a cron-job running that reminds organizers via email after at least X hours have passed.

[sueszli]

Woah this is a great description :)
[reminder to myself to update the mockups accordingly]

[sueszli]

Missing feature / enhancement that we could add in the future: Reminding the organizers if they didn't publish the matches after a while (otherwise this feature is implemented as described above)