feat: #67 add CLI arguments for analysts, model, and provider selection

[pixari]

CLI Arguments Enhancement

Overview

This PR introduces new command-line interface arguments to provide more flexibility in configuring the hedge fund simulation.

Changes

Added new CLI arguments to main.py:
--analysts: Allows specifying a comma-separated list of analysts (e.g., 'technical_analyst,fundamentals_analyst')
--model: Enables selection of specific LLM model (e.g., 'gpt-4')
--model-provider: Allows choosing the model provider (e.g., 'OpenAI')

Updated README.md with:

• Improved formatting and readability
• Added documentation for new CLI arguments
• Enhanced setup instructions

Impact:

These changes make the system more configurable, allowing users to:

• Customize which analysts are active in their simulation
• Choose specific LLM models for their use case
• Select different model providers based on their preferences

Closes #67

[chadtzeo]

The 'o' in GPT-4o stands for omni.