add custom file parser function

[7801943]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

with complex docx files，文档解析器 can't do parser well，so preceeding files by custom tools，apis，or code（in sandbox）need to be done

2. Additional context or comments

No response

3. Can you help us with this feature?

• I am interested in contributing to this feature.

[svcvit]

I have a relatively clever method; you can give it a try if needed. https://blog.vcvit.me/2024/12/05/use-dify-sandbox-to-parse-files/