[rag eval] add concept of feedback stage

[chejennifer]

• Add a new FeedbackStage enum to be used when deciding what to display in the query section and feedback sections
• Changes to make RIG eval tool work with this new concept
• only change made for RAG was displaying the rag calls in the query section when feedback stage is the CALLS stage. Actual navigation for RAG will come later

[chejennifer]

thanks for the review!