Setting AWS endpoints for Kinesis consumer

[louiscb]

It doesn't appear to be possible to set the endpoint the library points to for the aws services such as Kinesis and DynamoDb. Instead it appears that we are hard coded to point at the real aws service endpoint. It would be useful for local development to be able to set the endpoint ourselves. This way we aren't creating resources in our production aws cloud environment when running the example. We could supply the endpoint into the producer configuration map e.g:

    # a kinesis stream processor:
    kinesis_producer = %{
      kinesis_endpoint: "http://localhost:4567",
      dynamodb_endpoint: "http://localhost:8000",
      app_suffix: :k,
      kcl_appname: "erlang-processor-kinesis-test",
      stream_name: stream_name,
      stream_region: stream_region,
      stream_type: :kinesis,
    }