[DOC] Data Prepper S3 sink new features

[graytaylor0]

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Tell us about your request. Provide a summary of the request and all versions that are affected.
There have been some changes to the S3 sink

1. Support for dynamic path_prefix to group Events to different "folders" in the bucket - (Add creation and aggregation of dynamic S3 groups based on events data-prepper#4346)
2. Existing threshold is at the group level. Support for aggregate_threshold to limit total memory usage for high group cardinality cases - (Add aggregate_threshold with maximum_size to s3 sink data-prepper#4385)
3. Support for dynamic bucket name to send to different buckets dynamically, including a default_bucket parameter that will be sent to when a NoSuchBucketException or access denied exception is thrown.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.