Minimize costs of BatchReplayer with PreparedDatasets in multiple regions

[vgkowski]

Currently, PreparedDatasets are consumed from a single region (eu-west-1) and it generates cross region data transfer costs when provision a BatchReplayer in a different region.

We need to make the S3 Location of the PreparedDataset dynamic so it can point to a local S3 Location if it exists. Datasets can be replicated with Amazon S3 Cross Region Replication.