I don't want to remove them completely because they can still be used
for inspiration for writing new tests, but to me, "skipped test"
implies "bug that needs to be fixed", and these aren't bugs so much as
outright outdated code.
Closes#6665
Not having prefer-const on the JS side makes JS -> TS refactors really
unreadable. This commit just auto-fixes it so we're using
`prefer-const` everywhere.
By adding a `getGame` function of type:
```
// null is returned if the gameids don't match
// or the game doesn't exist
getGame<T extends RoomGame>(constructor: new (...args: any[]) => T) => T | null
```
(Credits @urkerab and @whalemer for the function signature.)
It allows refactoring previous code of:
```
if (room.game && room.game.gameid !== 'hangman') return;
const game = room.game as Hangman;
```
to:
```
const game = room.getGame(Hangman);
if (!game) return;
```
This has a couple of advantages:
- TypeScript will throw an error if the if condition is not present.
- In the new code, the template must extends `RoomGame` and be assignable to the same ID, so it's 100% typesafe
- The big change here is that player.userid can now be empty. You can
now fit state into RoomGamePlayer subclasses even when there are no
users associated with them.
- `game.players` has been introduced as the new canonical list of
players, including userless players. The old `game.players` has been
renamed `game.playerTable`, for clarity.
- `game.addPlayer` now returns the added player
All existing RoomGames have been updated for the new API, and
RoomBattle is now officially a RoomGame subclass.
Tournaments was also massively refactored to be properly updated for
the old API, since that never happened, and should now be a lot more
readable.
