Update post answering prompt to include images

[liammoat]

Required by #323

Description

When calling the /api/conversation/custom endpoint, generate embeddings of the question using computer vision and query the image embeddings using the question embeddings. We should continue to create question embeddings using text-embeddings-ada-002 in addition to be used to search the image description.

Tasks

_To be filled in by the engineer picking up the subtask

• Update post answering prompt to include images