Turning the "importsNotUsedAsValues" TS config value to "error".
This will require us to use `import type` instead of `import` when we are importing a value that is only used as a type (and therefore that is dropped by the Typescript compiler).
Why this change?
This is a requirement to be able to use Svelte in the future. See https://github.com/sveltejs/svelte-preprocess/issues/206#issuecomment-663193798
Now, when a user moves, only his/her position is sent back to the other users. The position of all users is not sent each time.
The messages sent to the browser are now:
- the list of all users as a return to the join_room event (you can send responses to events in socket.io)
- a "join_room" event sent when a new user joins the room
- a "user_moved" event when a user moved
- a "user_left" event when a user left the room
The GameScene tracks all these events and reacts accordingly.
Also, I made a number of refactoring in the classes and removed the GameSceneInterface that was useless (it was implemented by the LogincScene for no reason at all)
