[Feature] "Events" and matches being grouped as such

[BloodyIron]

We run multiple events, and as such, I anticipate this leading to a scaling issue over time.

I would like it if we could create an "event" where we tie matches to it. Let's say we declare the event by date, so when creating a match it automatically selects the active event, based on date.

Nothing too fancy, just so we, those running the event, and the participants, can tell "this match was for this event", "these other matches are for other events", as we don't really want to wipe the record clean for each event.

I don't think events should be a mandatory facet of get5-web, but I think this could really help us, and others, keep organised.