bugfixes and improvements

* fixed inconsistent player order
* minor visual adjustments
* refactoring

wizard-server/src/main/java/eu/jonahbauer/wizard/server/Session.java

@@ -35,7 +35,7 @@ public class Session implements Observer {
     private final Configuration configuration;
 
     @Getter(AccessLevel.NONE)
-    private final Map<UUID, SessionPlayer> players = new HashMap<>();
+    private final Map<UUID, SessionPlayer> players = new LinkedHashMap<>();
 
     private Game game;
     private final List<Pair<UUID, ServerMessage>> messages = new ArrayList<>();