Add support for S3 Bucket Key at the object level

S3 Bucket Keys reduce the cost of server-side encryption using AWS Key Management Service (AWS KMS) (SSE-KMS) by decreasing request traffic from Amazon S3 to AWS KMS. This request is to add support for enabling bucket key from Beam. 

Details: https://docs.aws.amazon.com/AmazonS3/latest/userguide/configuring-bucket-key-object.html