Qdrant metadata payload keys (#13001)
- **Description:** In Qdrant allows to input list of keys as the
content_payload_key to retrieve multiple fields (the generated document
will contain the dictionary {field: value} in a string),
- **Issue:** Previously we were able to retrieve only one field from the
vector database when making a search
- **Dependencies:**
- **Tag maintainer:**
- **Twitter handle:** @jb_dlb
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Co-authored-by: Jean Baptiste De La Broise <jeanbaptiste.delabroise@mdpi.com>