Create a Configuration for Default Language for Azure Agent

[bmkaiser]

Summary of the new feature / enhancement

The Azure agent defaults to Azure CLI, but I typically use Azure PowerShell. I can work around this by including "using Azure PowerShell" in my prompts, but I'd prefer to have it always default to Azure PowerShell.

Proposed technical implementation details (optional)

Add a configuration item to ~\.aish\agent-config\azure\az.config.json for default language for responses: Azure CLI, Azure PowerShell