Add OpenSearch AI demo

[labrenbe]

Create a demo showcasing Opensearch in an AI use case as vector store for a RAG.

The stack should include:

• OpenSearch
• ollama (MIT license) for generating embeddings from documents/prompts and hosting an LLM
• Jupyterhub with a pre-built notebook that shows how to interact with OpenSearch & the LLM

We should try to keep the resource requirements as low as possible to enable users to run the demo on their local machines. That's why the data ingestion should be done with a simple Kubernetes Job and not with another product from our stack like Spark.

The data used in the demo should be the official Stackable documentation.