go/worker/keymanager/status: Show active version of the km runtime

[peternose]

The status of the key manager was updated to include a new attribute called active_version, which stores the version number of the currently deployed key manager runtime. If no deployment is active, the value is set to null.

Result:

➜  oasis-post-upgrade oasis-node control status -a keymanager-1-internal-205141582.sock
{
  "keymanager": {
    "worker": {
      "active_version": {
        "minor": 1
      },
      "runtime_id": "c000000000000000ffffffffffffffffffffffffffffffffffffffffffffffff",
    }
  },
}