feat(emulation): declare RetroArch configuration

configs/nixos/modules/services/romm.nix

@@ -56,6 +56,13 @@ in
               default = "roms/{platform}/{game}";
               firmware = "bios/{platform}";
             };
+            scan.media = [
+              "box2d"
+              "screenshot"
+              "title_screen"
+              "logo"
+              "manual"
+            ];
           }
         );