:sparkles: api / auth

[fabienjuif]

fixes #62

TODOs

• [x] add two users
• [x] the game should ask for JWT token to accept a connection
• [x] ui should get token
• [x] ui should store token
• [x] ui should send a real token to the game

[fabienjuif]

@WesleyRUCHAUD this is the first version you can review.

I'll write the lobby after this.

Users are hardcoded for now.