AWS S3 component should respect the maxMessagesPerPoll

When checking for the existence of the bucket the AWS S3 endpoint does not respect the values set with maxMessagesPerPoll [1]. Although it's not a severe problem, it may lead to a small degradation in the route startup when dealing with very larger buckets or simply an undesired behavior for users setting the maxMessagesPerPoll option.

I'll send a PR for this.

1. https://github.com/apache/camel/blob/camel-3.0.0-RC3/components/camel-aws-s3/src/main/java/org/apache/camel/component/aws/s3/S3Endpoint.java#L102