Implement Weviate as a vector storage backend

Problem/Motivation

We currently only use Pinecone as a backend vector store. But his is proprietary and for data security issues may be an issue especially in the EU.

Steps to reproduce

Proposed resolution

Implement Weviate as an open source alternative https://weaviate.io/
(Could also look at newer version of Apache Solr when it supports vectors of size 1536 instead of the current 1024

Remaining tasks

User interface changes

API changes

Data model changes