Show rules on first connection (#5715)

* Implement showing rules on first connection

* Clean up RulesManager

* Change changelog and rules unread to use CVars

* Fix missing change

* Rename InfoWindow to RulesAndInfoWindow

* Change default server.id to unknown

* Fix invalid file contents and getting CVar

Content.Client/Preferences/UI/CharacterSetupGui.xaml.cs

@@ -67,7 +67,7 @@ namespace Content.Client.Preferences.UI
 
             UpdateUI();
 
-            RulesButton.OnPressed += _ => new InfoWindow().Open();
+            RulesButton.OnPressed += _ => new RulesAndInfoWindow().Open();
             preferencesManager.OnServerDataLoaded += UpdateUI;
         }