feat(embeddings builder): improve multi-field embed functionality

[marieaurore123]

Feature Request

The Embeddable trait should account for the case where a struct contains multiple fields to embed.

Motivation

Currently, when there are multiple fields of a struct that need to be embedded, the Embeddable trait method fn embedabble() creates a list of strings for those fields and concatenates them together as a single list of strings. There is no way to differentiate between the strings from field A and the strings from field B.

If the goal of creating embeddings is to add them to a vector store afterwards, it may not be the desired effect to store the vector embeddings of multiple fields into a single field of the vector store.

Proposal

I don't know yet.