Add RAG pipeline

[FrancisTembo]

Objective
Implement a RAG pipeline to enable an LLM to answer queries about research objects in the index. Example questions include:

• What are the latest CCG research findings from Kenya?
• Are there any active clean cooking projects in Kenya?
• What is [insert_author]’s most recent research?

References

1. https://medium.com/@zilliz_learn/graphrag-explained-enhancing-rag-with-knowledge-graphs-3312065f99e1
2. https://neo4j.com/developer-blog/knowledge-graph-rag-application/
3. https://github.com/neo4j/neo4j-graphrag-python
4. https://neo4j.com/blog/graphrag-manifesto/