feat: add steam_disk_space egg feature to SteamCMD eggs

A new egg feature modal was introduced in Panel v1.7.0 triggering when server has run out of disk space to provide more user-friendly instructions to both admins and normal users. This is unique to SteamCMD specific errors.

game_eggs/steamcmd_servers/assetto_corsa/egg-assetto-corsa.json

@@ -8,7 +8,9 @@
     "name": "Assetto Corsa",
     "author": "admin@softwarenoob.com",
     "description": "Assetto Corsa (Italian for \"Race Setup\") is a sim racing video game developed by the Italian video game developer Kunos Simulazioni. It is designed with an emphasis on a realistic racing experience with support for extensive customization and moddability",
-    "features": null,
+    "features": [
+        "steam_disk_space"
+    ],
     "images": [
         "ghcr.io\/parkervcp\/games:source"
     ],
@@ -119,4 +121,4 @@
             "rules": "required|string|max:20"
         }
     ]
-}
+}