Steam Deck Support + Migration to UE5.6

[p]Hi everyone![/p]

• [p]Game migrated to UE 5.6[/p]
• [p]Steam Deck build is sent for certification.
  (to play it now use "steam_deck_win" beta branch - it's good)[/p]
• [p]Native Linux support for Deck is also pending certification.[/p]
• [p]Bigger font mode is activated for Steam Deck, but also available as launch option -UseBiggerFont.[/p]
• [p]Fix for level editor skipped terrain generation stage.[/p]

[p][/p][p]Game is solid, and everything is ready for the production of our first Skirmish map.
Stay tuned![/p]