[Release] Docs Agent version 0.3.0

[kyolee415]

What's changed:

• Refactoring of Docs Agent to support a more modularized architecture.
• Added features:
  • Benchmarking: Includes benchmark test to measure the quality of AI generated responses.
  • Semantic Retrieval API: Supports using Gemini's Semantic Retrieval API to store text chunks online and the AQA model for question-answering.
  • Docs Agent CLI: Allows easy management of chunking documents, populating a vector database, launching the chatbot and more.

Description of the change

A major refactoring of Docs Agent, plus the Semantic Retrieval API and AQA model integration and new Docs Agent CLI added. See the details above.

Motivation

Refactoring and new features

Type of change

Choose one: (Feature request)

Checklist

• [ X] I have performed a self-review of my code.
• [ X] I have added detailed comments to my code where applicable.
• [ X] I have verified that my change does not break existing code.
• [ X] My PR is based on the latest changes of the main branch (if unsure, please run git pull --rebase upstream main).
• [ X] I am familiar with the Google Style Guide for the language I have coded in.
• [ X] I have read through the Contributing Guide and signed the Contributor License Agreement.