feat: define variant node kinds

[okjodom]

Requires redefining config in the shape below

 "nodes": [
    {
      "LND": {
        "id": "",
        "address": "",
        "macaroon": "",
        "cert": ""
      }
    },
    {
      "CLN": {
        "id": "",
        "address": "",
        "ca_pem": "",
        "client_pem": "",
        "client_cert": "",
      }
    }
  ],
  "activities": []

[carlaKC]

Requests from our warnet friends:

 "nodes": [
    {
        "impl": "LND",
        "id": "",
        "address": "",
        "macaroon": "",
        "cert": ""
  },
  {
        "impl": "CLN",
        "id": "",
        "address": "",
        "macaroon": "",
        "cert": ""
    },
  ],

[okjodom]

closed in favor of #74 and #75