feat: Chunker module enabling custom chunking strategy

[AveryYay]

Description

Implemented a chunker module enabling custom chunking strategy.

Checklist

Go over all the following points, and put an x in all the boxes that apply.

• [x] I have read the CONTRIBUTION guide (required)
• [x] I have linked this PR to an issue using the Development section on the right sidebar or by adding Fixes #issue-number in the PR description (required)
• [x] I have checked if any dependencies need to be added or updated in pyproject.toml and poetry.lock
• [ ] I have updated the tests accordingly (required for a bug fix or a new feature)
• [x] I have updated the documentation if needed:
• [ ] I have added examples if this is a new feature

[Wendong-Fan]

please also pay attention to PR naming