Support for TreeHub in GKE

[doanac]

I'm currently running TreeHub in Google Kubernetes Engine (GKE) cluster. Google storage supports interoperability with S3 buckets. I think the only thing required to make TreeHub work with this is a new optional config field maybe something like endpointUrl. And then the s3 client constructor (pardon my lack of Scala know-how) might be something like:

 private lazy val s3client = AmazonS3ClientBuilder.standard()
      .withCredentials(s3Credentials)
      .withRegion(s3Credentials.region)
      .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(s3Credentials.endpointUrl).build();
.build()

Any interest in adding support for this?

[simao]

Yes, we could merge a PR adding support for this.