metadata - enhance the "default" to keywords,topic etc.

[mamema]

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

with introducing metadata, the query possibilities were better. But the addition of metadata is manual (enter name, enter value)

PDfs are providing by default standard fields which could be used during search/embedding if they are already populated like for example keywords

2. Additional context or comments

No response

3. Can you help us with this feature?

• [ ] I am interested in contributing to this feature.