Adding LinearShardSpec and ACL on S3 object

I added LinearShardingSpec under shard package and LinearPartitionChunk under partition package. This is a little different from SingleDimensionShardSpec. LinearShardSpec is necessary for increasing and decreasing druid realtime cluster size dynamically on demand. Meanwhile, SingleDimensionShardSpec requires predefined the number of shards.

I want to add REST_CANNED_BUCKET_OWNER_FULL_CONTROL to the s3 object. I know this might be very specific request in Netflix environment. The problem is, in eu-west-1 AWS, the account of druid ec2 instance is different from the account managing s3 bucket. So, without this ACL, lifecycle rule of s3 bucket is not being applied in eu-west-1. Also, you may know I cannot override the ACL out of druid core context.