feat: Add Chunking Strategies: Regex and Substring Methods

[NailaRais]

Because

This PR is essential for enhancing the functionality and usability of our text processing capabilities. By introducing Regex and Substring chunking methods, we empower users to customize their text handling according to specific needs, ultimately improving their experience. The ability to define custom chunking rules through regular expressions and predefined indices offers greater flexibility and efficiency, especially when dealing with complex text formats. Additionally, this update aligns with our project requirements, ensuring we meet user demands for diverse text processing strategies. Implementing these features not only addresses current needs but also lays the groundwork for future enhancements based on user feedback, making this PR a crucial addition to the project.

This commit

1. Added Regex Chunking Method:

Implemented the Regex chunking method, allowing users to specify custom regular expression patterns for text splitting.
Introduced properties for chunk-size, chunk-overlap, model-name, and pattern to configure the chunking behavior.

2. Added Substring Chunking Method:

Implemented the Substring chunking method, enabling users to define start and end indices for chunking the text.
Introduced properties for chunk-size, chunk-overlap, model-name, start-index, and end-index for detailed configuration.

3. Updated JSON Schema:

Enhanced the existing JSON schema to include the new chunking strategies within the strategy properties.
It is ensured all new properties are properly documented and formatted for clarity and usability.