Add better seat resolution

[j-toscani]

Description (five sentences max.)
Seats were implemented to decouple the game from the players, so that if a player disconnects, another can rejoin. However, as the cards are connected to players rather than seats I cannot calculate which seat got how many points. If I reference the seat with the card on the table, I will have problems with statstics.

Possible implementation
Add both seat and user id to the card on the table

Acceptance Criteria
Both player and seat are referenced in the card on a Table

Out of Scope

• Storing of statistics
• Creating rejoin logic

Document optional improvements
Optional. Could lead to a better feature.