Add property to configure for your own endpoint url

[djemerson01]

Adding the ability to set your own endpoint url would make it possible to use this plugin with Localstack. For instance, I can easily create my own endpoint configuration to be passed to the S3 client builder for use with Localstack as follows:

public static AmazonS3 s3Client()
{
    AwsClientBuilder.EndpointConfiguration endpoint =
        new AwsClientBuilder.EndpointConfiguration("http://localhost:4572",
            "us-east-2");

    return AmazonS3ClientBuilder
        .standard()
        .withPathStyleAccessEnabled(true)
        .withEndpointConfiguration(endpoint)
        .withCredentials(new AWSStaticCredentialsProvider(new AnonymousAWSCredentials()))
        .build();
}

If I could just set the endpoint URL as a property, I'd be able to run your plugin against Localstack. This seems like an easy fix. Let me know if I'm missing something obvious.

Thanks.