feat: Add EmuDeck to yafti in deck images

system_files/deck/usr/share/ublue-os/firstboot/yafti.yml

@@ -137,6 +137,12 @@ screens:
       show_terminal: true
       package_manager: yafti.plugin.run
       groups:
+        EmuDeck:
+          description: |
+            Retrieves EmuDeck, a utility for installing and configuring emulators on the Steam Deck
+          default: true
+          packages:
+          - EmuDeck: just get-emudeck
         Memory Tuning:
           description: Adjust ZRAM and configure deckswap
           default: false