Add e2e tutorial for Nemo Evaluator

[yyu22]

The end to end tutorial covers the following topics and is verified on 25.06:

• Agentic Evaluation
• LLM Evaluation on Academic Benchmarks
• Custom Evaluations
  • Similarity Metrics Evaluation
  • LLM-as-Judge Evaluation
  • Tool Calling Evaluation
• Retriever Pipeline Evaluation
• RAG Pipeline Evaluation