Add setup script and update README with alternative installation instructions

[bannawandoor27]

This PR introduces a newsetup.sh script that provides an alternative installation method using Python's virtual environment (venv) alongside the existing conda-based setup. The script automates the following tasks:

• Creates and activates a Python virtual environment

• Installs all required dependencies

• Downloads necessary model checkpoints from HuggingFace

• Handles proper renaming of model directories
  Key Features:

• Provides a simpler installation option for users who prefer not to use conda

• Maintains backward compatibility with existing conda setup

• Automates model weight downloads and directory structure setup

• Includes clear post-installation instructions
  The setup script has been tested to ensure it properly:

• Creates the virtual environment

• Installs dependencies from requirements.txt

• Downloads model checkpoints from microsoft/OmniParser-v2.0

• Correctly renames the icon_caption directory to icon_caption_florence
  This addition makes the installation process more flexible while maintaining the existing functionality for conda users.

[bannawandoor27]

@microsoft-github-policy-service agree