Add state management to tournaments

[evroon]

spinoff from: #650

7. Tournament States: Define states such as [Draft], [Running], and [Archived] to manage the tournament lifecycle more effectively. In the [Draft] state, all data can be modified without entering match results. Once in the [Running] state, only match results should be updatable. Finally, the [Archived] state would freeze all data, allowing only queries.

We should implement archiving tournaments and making them read-only.

In running state, more should be able to be updated than just match results IMO. Bracket should be flexible enough (and already is) to handle changes to team setups or changing team names etc. during tournaments, which is an important feature that other tools don't have.

The draft state is IMO just the same as the regular state, except that it isn't visible publicly (for which option there is already support), so I don't think we need that.