feat: implement method to start a game

src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameStateManager.java

@@ -53,6 +53,14 @@ class GameStateManager {
         return (Event[])GameLogic.checkTurnEnd(state).toArray();
     }
 
+    /**
+     * Starts the game.
+     * @return The resulting {@link Event}s
+     */
+    public Event[] startGame() {
+        return (Event[])GameLogic.handleTurnEnd(state).toArray();
+    }
+
     /**
      * Applies an array of {@link Event}s to the game state.
      * @param events The events to apply