Modify bridge scanner web API to include the consensus ratio threshold and the bridge ratio

After talking with @meskio, we have thought that for rdsys to accept both answers from bridgestrap and onbasca, we should modify the onbasca API to return 2 more fields in its JSON, one for the bridge ratio threshold (rdsys doesn't obtain the consensus) and another for the ratio of each bridge.

So the onbasca JSON would be:

  {
    "bridge_results": {
      "BRIDGE_LINE_1": {
        "functional": BOOL,
        "last_tested": "STRING",
        "error": "STRING", (only present if "functional" is false)
        "ratio": FLOAT
      },
      ...
      "BRIDGE_LINE_N": {
        ...
      }
    },
    "error": "STRING", (only present if the entire test failed)
    "time": FLOAT,
    "bridge_ratio_threshold": FLOAT
  }