Pre-install VS Code extensions in desktop VS Code module

[matifali]

Extend the VS Code desktop module to automatically install specified extensions. Should accept extension list as parameter and configure workspace-specific settings.

[yashksaini-coder]

/attempt #207

My appraoch it to Add an extra extensions parameter that accepts a list of extension IDs. Create a new run.sh script that uses code --install-extension to install each extension during VM provisioning after VS Code setup. Include basic error handling and ensure proper user context for persistent installations.

[yashksaini-coder]

@matifali I have raised PR, for this issue, #218