The control plane learns 'prepares' one release before its manifest uses it

A manifest word has to reach every parser before a manifest carries it. The builder refused
mesh-controller's manifest with `unknown field "prepares"` until it was rebuilt; then the running
control plane could not read the manifest in the build result either, so the build was recorded with
no module and the version never moved. Strict parsing is deliberate (novox/hq 04-ISSUES/003), so the
word ships first and a manifest uses it next: this takes `prepares` back out of the control plane's
own manifest, leaving the code that understands it, and the manifest says it again once this is
running everywhere.

module.json

@@ -27,7 +27,6 @@
     "bus": "/var/lib/mesh/mesh-controller/bus"
   },
   "secrets-owner": "65534:65534",
-  "prepares": true,
   "resources": [
     {
       "id": "mesh-state",