[Feature] Better spectator management for matches

[BloodyIron]

With the get5-web pre-fork, we could add one spectator to a match, but not more, and we could not quite tell which was added after the fact.

I would like it if:

1. We could see which spectators are allocated to a match.
2. We could pre-define spectator group(s), and add either individual spectators and/or groups to a match.
3. Have the ability to remove individual/group spectator(s) from a match.
4. Order pizza for spectators (this feature may not 100% be serious).

Maybe have spectator groups tied per-event, not sure?