Improve Azure Functions support

[kenmuse]

To make it easier for users to deploy the sample on Azure Functions, we need the following features:

• [x] Separate code for the Function handler
• [x] Automate Functions build
• [x] Implement Feature for Dev Container with required tools
• [ ] Bicep file for deploying Function on Azure Container Apps with Key Vault
• [ ] Release image: Container image (requires workflow)
• [ ] Bicep file for deploying on Azure Functions with Key Vault
• [ ] Release image: Functions ZIP package (requires workflow)
• [ ] Add documentation for deploying to /docs folder

Stretch goals:

• [ ] Add integration tests
• [ ] Bicep files committed with built ARM templates
• [ ] Azure UI implemented to prompt user for deployment variables (APP_ID, etc.)
• [ ] "Deploy to Azure" link configuration for deploying the ARM file to Azure