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/scpsl/dedicated/egg-scpsl.json

@@ -8,7 +8,9 @@
     "name": "SCP:SL",
     "author": "info@goover.de",
     "description": "Egg for SCP: Secret Laboratory Dedicated Linux Server",
-    "features": null,
+    "features": [
+        "steam_disk_space"
+    ],
     "images": [
         "ghcr.io\/parkervcp\/yolks:mono_latest"
     ],

game_eggs/steamcmd_servers/scpsl/exiled/egg-s-c-p--s-l--exiled.json

@@ -8,7 +8,9 @@
     "name": "SCP:SL - Exiled",
     "author": "info@goover.de",
     "description": "Egg for SCP: Secret Laboratory Dedicated Linux Server with Exiled Plugin Framework",
-    "features": null,
+    "features": [
+        "steam_disk_space"
+    ],
     "images": [
         "ghcr.io\/parkervcp\/yolks:mono_latest"
     ],

game_eggs/steamcmd_servers/scpsl/multiadmin/egg-s-c-p--secret-laboratory--multi-admin.json

@@ -8,7 +8,9 @@
     "name": "SCP: Secret Laboratory - MultiAdmin",
     "author": "info@goover.de",
     "description": "The latest vanilla version of SCP:SL running through MultiAdmin for compatibility. LocalAdmin does not work. No SMod2.",
-    "features": null,
+    "features": [
+        "steam_disk_space"
+    ],
     "images": [
         "ghcr.io\/parkervcp\/yolks:mono_latest"
     ],
@@ -47,4 +49,4 @@
             "rules": "required|integer"
         }
     ]
-}
+}