(bedrock): s3-data-source - add hierarchical and semantic chunking support

[aws-rafams]

Describe the feature

It would be useful to add support to hierarchical and semantic chunking, besides the already supported, fixed size.

generative-ai-cdk-constructs/src/cdk-lib/bedrock/s3-data-source.ts

Lines 32 to 50 in 16e15cd

	export enum ChunkingStrategy {
	/**
	* Amazon Bedrock splits your source data into chunks of the approximate size
	* that you set in the `fixedSizeChunkingConfiguration`.
	*/
	FIXED_SIZE = 'FIXED_SIZE',
	/**
	* `FIXED_SIZE` with the default chunk size of 300 tokens and 20% overlap.
	* If default is selected, chunk size and overlap set by the user will be
	* ignored.
	*/
	DEFAULT = 'DEFAULT',
	/**
	* Amazon Bedrock treats each file as one chunk. If you choose this option,
	* you may want to pre-process your documents by splitting them into separate
	* files.
	*/
	NONE = 'NONE',
	}

https://docs.aws.amazon.com/bedrock/latest/userguide/kb-chunking-parsing.html#kb-hiearchical-chunking
https://docs.aws.amazon.com/bedrock/latest/userguide/kb-chunking-parsing.html#kb-semantic-chunking

Use Case

Semantic chunking improves retrieval accuracy by focusing on the semantic content rather than just syntactic structure.

Proposed Solution

modify s3-data-source.ts module

Other Information

Semantic and Hierarchical Chunking are already supported by L1 construct
https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_bedrock.CfnDataSource.ChunkingConfigurationProperty.html#chunkingstrategy

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

[krokoko]

closing as duplicate of #587
The new chunking strategies and associated parameters (see here) are available in cfn but not in cdk yet. They should be added in an upcoming release, we will then implement it.