[FEATURE] Allow more content type for neural query with multimodal

[martin-gaievski]

Is your feature request related to a problem?

Currently neural-search supports text and image fields for generation of embeddings in both ingestion and search. Content can be of other types like audio or video information, and that is not supported today, e.g. for search there are only query_text and query_image fields.

What solution would you like?

Ability to pass content like audio or video for data ingestion and search.

What alternatives have you considered?

We can use other solutions to generate embeddings for audio or video content, and then post process results from OpenSearch and other systems.

Do you have any additional context?

It's a good extension for https://github.com/opensearch-project/neural-search/issues/318