Expose lnuri, connexturi, connextchanneladdress on listpeers

[kilrau]

Currently we only expose ln pubkeys, but not the full lnuri, nothing for connext:

Problem:
    {
      "address": "127.0.0.1:33870",
      "nodePubKey": "027178f1a99b1b39aeeb53192ad05f617963abba7731d1e7146302e779ed524608",
      "lndPubKeysMap": [
        [
          "BTC",
          "03e2496e71b524a3144aa4897487823803f1cc8a74ff7d912a331f4d5a9e1e6bf0"
        ],
        [
          "LTC",
          "03269a47ebba056ba66a6dcee35d5366bbdf845a13f2cef2ef205f6c2fbcfaad83"
        ]
      ],
      "inbound": true,
      "pairsList": [
        "ETH/BTC",
        "LTC/BTC",
        "LTC/USDT",
        "BTC/USDT",
        "USDT/DAI"
      ],
      "xudVersion": "1.2.2",
      "secondsConnected": 4127,
      "alias": "BulkSound"
    }
  ]
}

We want to expose the full lnuri, connexturi and additionally the connext "channel address" in listpeers. Depends on https://github.com/ExchangeUnion/xud/pull/1938

[erkarl]

Think we just want to expose connextIdentifier here. It's already being broadcasted via the p2p layer.