Add Azure AI Foundry workspace service

[marrobi]

Fixes #4509

This PR adds a new Azure AI Foundry workspace service template.

Features

• Azure AI Hub with Azure OpenAI integration
• Private endpoint connectivity for all resources
• Role-based access control for workspace owners and researchers
• Optional Azure AI Search for RAG and knowledge retrieval scenarios
• Optional Azure Cosmos DB for agent state persistence and conversation history
• Optional VNet injection for Standard Agents (can take 30-60+ min)

Status

⚠️ Draft - Further testing required

• ✅ Basic deployment works
• ⏳ Cosmos DB integration - needs testing
• ⏳ AI Search integration - needs testing
• ⏳ Agent VNet injection - needs testing

Usage

# Basic deployment
tre workspace-service create --workspace <id> --template ai-foundry

# With optional features
tre workspace-service create --workspace <id> --template ai-foundry \
  --parameter enable_ai_search=true \
  --parameter enable_cosmos_db=true

[github-actions]

Unit Test Results

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Results for commit afa9c39.

[marrobi]

@TonyWildish @JaimieWi I know there has been interest in this. I have been using it in demos to work with LLMs deployed in the TRE workspace VNet, but needs finishing off...