GUI: reworked GUI to support non-blocking UI:

- GUI: added non-blocking UI to almost all app and game dialogs;
- GUI: it allows to switch between UI dialogs and use any UI elements at any moment;
- GUI: it allows to use chat, card popup, battlefield, concede and other features while choosing (related to #12670);
- GUI: it allows to download images while playing (related to #4160, not fully tested);
- GUI: enabled by default, can be disabled by java option: -Dxmage.guiModalMode=true
- connection: auto-connect will be visible in main menu on startup;
- connection: removed some unused features (auto-connect by command line);
- connection: added <ESC> button to close connection dialog;
- download: added background images download (see non-blocking UI);
- download: improved cancel stability and fixes that it can't stop preparing/downloading process in some use cases;
- app: fixed freezes on macOS systems in some use cases (related to #12431, #11292, #9300, #4920);

Mage.Client/src/main/java/mage/client/dialog/TestCardRenderDialog.java

@@ -113,11 +113,7 @@ public class TestCardRenderDialog extends MageDialog {
 
         // windows settings
         MageFrame.getDesktop().remove(this);
-        if (this.isModal()) {
-            MageFrame.getDesktop().add(this, JLayeredPane.MODAL_LAYER);
-        } else {
-            MageFrame.getDesktop().add(this, JLayeredPane.PALETTE_LAYER);
-        }
+        MageFrame.getDesktop().add(this, this.isModal() ? JLayeredPane.MODAL_LAYER : JLayeredPane.PALETTE_LAYER);
         this.makeWindowCentered();
 
         // Close on "ESC"