Feature Request: Collection of vector fields

For our use case, we are ingesting long documents and audio transcripts. The amount of text we're starting with exceeds the 8K limit of the Ada embedding model.

So we need to create multiple embeddings from each piece of content.

Since we can only store one vector per search document, I had to come up with a hacky solution to store 'n' search documents per content. (Basically one parent search document, and 'n' child search documents, n == # of chunks).

If the Cog Search index could support a collection of complex types, each which included a vector, it would make this scenario much cleaner for these use cases.

Currently, it errors with "Only a top-level field of the index can be a vector field."