Add create lobby game endpoint

[donbonifacio]

Did some refactoring to start using component and schema. Created the /lobby/create-game endpoint that creates a (still empty) game.

Next steps:

• The lobby websocket, that will receive events on the lobby
• The join endpoint, that removes the game from the lobby and starts the game
• The play endpoint
• The client side code that uses bots to create and play games

[jqmtor]

@donbonifacio , sorry for the quite extensive review, specially in cases where it is really not that important. I am also using this to understand the reasoning of your choices and to get some guidance on how to do things in this new paradigm. Won't give so much trouble with this stuff at some point :)

👍 Great work and thanks a lot for the explanations! Feel free to merge :)