Crosswordpuzzle: improve QoL

[madebyTimo]

Description

Currectly the Crosswordpuzzle is not really nice to play. This has to be improved

DoD

• [x] The next Field is selected automatically when a letter is entered
• [x] Add exit button

[madebyTimo]

Before working on this issue please play the game a few times and extend the DoD!