Update README and agent initialization for enhanced clarity and functionality

- Revised the README.md to better describe PraisonAI as a production-ready Multi-AI Agents framework, emphasizing its capabilities in automating tasks and problem-solving.
- Updated the list of features to include new agent types and functionalities, such as Code Interpreter Agents and Async & Parallel Processing.
- Simplified the agent initialization examples in the README, providing clearer instructions for users to create and run agents.
- Modified the agent client initialization in main.py to handle missing API keys more gracefully.
- Added "developers/local-development" to mint.json for improved documentation structure.

These changes enhance the user experience by providing clearer documentation and improving the robustness of agent initialization.

Author: MervinPraison