The control plane's declaration lives with the control plane

A module is a repository and a path within it, and the manifest sits at that
path. This one sat in the catalogue instead, so the thing that says what the
control plane is and the thing it is made of lived in different repositories
and could drift apart with nothing to notice.

It also names an artifact it builds rather than a placeholder digest somebody
fills in, which is what lets the mesh build its own control plane.

module.json

@@ -0,0 +1,68 @@
+{
+  "module": "mesh-control",
+  "version": "1",
+  "slug": "control",
+  "capabilities": [
+    "container-runtime"
+  ],
+  "claims": [
+    {
+      "name": "the-control-plane",
+      "scope": "mesh"
+    }
+  ],
+  "own-secrets": {
+    "inventory": "/var/lib/mesh/mesh-control/inventory",
+    "identity": "/var/lib/mesh/mesh-control/identity",
+    "licences": "/var/lib/mesh/mesh-control/licences",
+    "broker": "/var/lib/mesh/mesh-control/broker",
+    "broker-management": "/var/lib/mesh/mesh-control/broker-management",
+    "broker-address": "/var/lib/mesh/mesh-control/broker-address"
+  },
+  "resources": [
+    {
+      "id": "mesh-state",
+      "type": "directory",
+      "path": "/var/lib/mesh/mesh-control",
+      "mode": "0700"
+    },
+    {
+      "id": "control-env",
+      "type": "file",
+      "path": "/var/lib/mesh/mesh-control/control.env",
+      "mode": "0600",
+      "content": "MESH_STORE_INVENTORY=${secret:inventory}\nMESH_STORE_IDENTITY=${secret:identity}\nMESH_STORE_LICENCES=${secret:licences}\nMESH_BROKER_AMQP=${secret:broker}\nMESH_BROKER_MANAGEMENT=${secret:broker-management}\nMESH_BROKER_ADDRESS=${secret:broker-address}\n"
+    },
+    {
+      "id": "server",
+      "type": "container",
+      "name": "mesh-control",
+      "network": "host",
+      "args": [
+        "serve"
+      ],
+      "env-file": [
+        "/var/lib/mesh/mesh-control/control.env"
+      ],
+      "env": {
+        "MESH_BROKER_CERTIFICATE": "/broker-tls/tls.crt"
+      },
+      "volumes": [
+        "mesh-broker-tls:/broker-tls:ro"
+      ],
+      "restart-on": [
+        "control-env"
+      ],
+      "artifact": "server"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "server",
+        "kind": "image",
+        "from": "Dockerfile"
+      }
+    ]
+  }
+}