Vector search support for llama-index with metadata

Llama-index is a super useful and performant tool for creating the vector store within iris, however the current integration between iris and llama-index doesn't support metadata (a capability of newer versions of llama-index). This would be a very helpful feature for many applications, for example where a hybrid search of documents is required (e.g. filtering by date or author of a document before doing a vector search). Currently, the workaround would be to build a normal SQL database and populate the embeddings, metadata, text chunks etc. yourself, however being able to do this directly with llama-index would be highly convenient.