Add support for subscriptions

api/system/spec.json

@@ -310,6 +310,20 @@
       }
     ]
   },
+  {
+    "title": "Subscription",
+    "path": "/subscription",
+    "entrypoint": "subscription",
+    "apis": [
+      {
+        "name": "current",
+        "method": "GET",
+        "title": "Returns current subscription status",
+        "path": "/",
+        "parameters": {}
+      }
+    ]
+  },
   {
   "title": "Organisations",
   "description": "Organisations represent a top-level grouping entity. There may be many organisations defined in a single deployment.",

api/system/spec/subscription.json

@@ -0,0 +1,18 @@
+{
+  "Title": "Subscription",
+  "Interface": "Subscription",
+  "Struct": null,
+  "Parameters": null,
+  "Protocol": "",
+  "Authentication": null,
+  "Path": "/subscription",
+  "APIs": [
+    {
+      "Name": "current",
+      "Method": "GET",
+      "Title": "Returns current subscription status",
+      "Path": "/",
+      "Parameters": {}
+    }
+  ]
+}