kvm: improve and rectify kvm's input json schema for parameter nat-rules

software/kvm/instance-kvm-input-schema.json

@@ -278,8 +278,9 @@
     },
     "nat-rules": {
       "title": "List of rules for NAT of QEMU user mode network stack.",
-      "description": "List of rules for NAT of QEMU user mode network stack, as comma-separated list of ports (with optional protocol). For each port specified, it will redirect port x of the VM (example: 80, udp:53) to the port x + 10000 of the public IPv6 (example: 10080, udp:10053). Defaults to \"22 80 443\". Ignored if \"use-tap\" parameter is enabled.",
-      "type": "string"
+      "description": "List of rules for NAT of QEMU user mode network stack, as space-separated list of ports (with optional protocol). For each port specified, it will redirect port x of the VM (example: \"80 udp:53\") to the port x + 10000 of the public IPv6 of the host (example: \"10080 udp:10053\"). Ignored if \"use-tap\" parameter is enabled.",
+      "type": "string",
+      "default": "22 80 443"
     },
     "nat-restrict-mode": {
       "title": "Isolate the NAT Interface (No Internet access)",