Add metricName to CircuitBreaker informations

[mcweba]

The CircuitBreaker provides an API to list all circuits with the current state, failRatio and path. The output looks like this:

{
  "a2e76944bdf41d97b7621d28c956d493":{
    "status":"closed",
    "infos":{
      "failRatio":0,
      "circuit":"/some/incident/tracking/events/(.*)"
    }
  },
  "6793ad399d83ffcd0168e18172304af0":{
    "status":"closed",
    "infos":{
      "failRatio":20,
      "circuit":"/some/v1/office/zips/(99989[0-1])/(.*)"
    }
  },
  "533ba84e5bd77e1a8e71c37f6c81db9a":{
    "status":"open",
    "infos":{
      "failRatio":100,
      "circuit":"/some/v1/stop-completion/"
    }
  }
}

To simplify the link between a routing rule and the corresponding CircuitBreaker values, we would like to store not only the circuit(aka path of the routing rule), but also the metricName.

The new output could look something like this:

{
  "a2e76944bdf41d97b7621d28c956d493":{
    "status":"closed",
    "infos":{
      "metric": "tracking-events",
      "failRatio":0,
      "circuit":"/some/incident/tracking/events/(.*)"
    }
  },
  "6793ad399d83ffcd0168e18172304af0":{
    "status":"closed",
    "infos":{
      "failRatio":20,
      "circuit":"/some/v1/office/zips/(99989[0-1])/(.*)"
    }
  },
  "533ba84e5bd77e1a8e71c37f6c81db9a":{
    "status":"open",
    "infos":{
      "metric": "stop-completion",
      "failRatio":100,
      "circuit":"/some/v1/stop-completion/"
    }
  }
}