Add button to temporary hide all game dialogs

[JayDi85]

Problem: many choose dialogs use a modal state, so users can't close/hide it or click on another button until making a choice. It's a problem cause users want to see a battlefield, chatting or card researching before making a choice.

MTGA solve it as special eye button to show battlefield without any dialogs.

XMage can use same feature, but it can be hard to implement (xmage/swing uses shared layer for all modal dialogs). So must be researched (is it possible or not).

TODO:

• move game modal dialogs from global to to game panels (make it not really modal);
• add button to temporary hide/show all dialogs on battlefield.

[JayDi85]

Alternative solution: disable modal mode at all (e.g. use callbacks instead blocking UI — any windows and dialogs can be switches at any time).

It works fine but introduce a buggy (important fox xmage) and a limited UX logic with max dialogs depth (non important to xmage — there are 1-2 max dialog chain like “main -> connect dialog -> search flag dialog”).

Bonus features:

• images downloading in background (UX improvements: background images downloading on first request #4160);
• possible macOS freeze fix (Mac Client freezes when launching new tourney #4920);
• workable card hints, battlefield and chats while choosing;
• etc.

TODO:

• add modal and non-modal support to current dialogs (add callback usage instead modal result);
• add app param to switch between modal and non-modal GUI (for dev tests);
• migrate all JDialog to MageDialog;
• research and add wrong data send protection for game panels (client must send only last modal data to the server, not any other clicks and choices — so all client side dialogs in the game must be limited to 1 depth -- it's server side feature to process wrong requests, not GUI)

[JayDi85]

Not actual anymore with non-blocking UI in last release #12825