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/eco/egg-eco.json

@@ -8,7 +8,9 @@
     "name": "Eco",
     "author": "info@goover.de",
     "description": "Eco is an online world from Strange Loop Games where players must build civilization using resources from an ecosystem that can be damaged and destroyed. The world of Eco is an incredibly reactive one, and whatever any player does in the world affects the underlying ecosystem.",
-    "features": null,
+    "features": [
+        "steam_disk_space"
+    ],
     "images": [
         "quay.io\/parkervcp\/pterodactyl-images:debian_dotnet-5"
     ],
@@ -92,4 +94,4 @@
             "rules": "required|string|max:50"
         }
     ]
-}
+}