Implement chain integration without DapiDataRegistry

[Siegrift]

Airseeker should have a chain configuration and read DapiDataRegistry contract for signed data API URL (not yet created) and Api3ServerV1 to fetch the data feed ID from data feed name.

Because the DapiDataRegistry is not yet created, we put the these into the config file. The config section format will be the following:

"__Temporary__DapiDataRegistry": {
  "airnodeToSignedApiUrl": {
    "0xbF3137b0a7574563a23a8fC8badC6537F98197CC": "http://127.0.0.1:8090/"
  },
  "dataFeedIdToBeacons": {
    "0xebba8507d616ed80766292d200a3598fdba656d9938cecc392765d4a284a69a4": [
      {
        "airnode": "0xbF3137b0a7574563a23a8fC8badC6537F98197CC",
        "templateId": "0xcc35bd1800c06c12856a87311dd95bfcbb3add875844021d59a929d79f3c99bd"
      }
    ]
  }
}