Add recommendations feature documentation

[flanakin]

🛠️ Description

Add documentation for the new hubs recommendations feature:

• New configure-recommendations.md page explaining how to configure built-in and custom recommendations
• Update template.md with new recommendation parameters
• Update changelog.md with recommendations feature entry
• Update TOC.yml to include the new page
• Update best practices pages (compute, databases, general, networking, storage) with recommendation-related guidance

📋 Checklist

🔬 How did you test this change?

• 🤏 Lint tests

🙋‍♀️ Do any of the following that apply?

• 🚨 This is a breaking change.
• 🤏 The change is less than 20 lines of code.

📑 Did you update docs/changelog.md?

• ✅ Updated changelog (required for dev PRs)

📖 Did you update documentation?

• ✅ Public docs in docs-mslearn (required for dev)

[Copilot]

Pull request overview

This PR adds comprehensive documentation for the new FinOps hubs recommendations feature, which enables automatic ingestion of Azure Advisor cost recommendations and custom Azure Resource Graph queries to identify optimization opportunities.

Changes:

• New configuration guide explaining how to use built-in and custom recommendations
• Updated deployment template documentation with new recommendation-related parameters
• Enhanced best practices pages with cross-references to the recommendations feature
• Updated changelog and navigation structure

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
docs-mslearn/toolkit/hubs/configure-recommendations.md	New comprehensive guide for configuring recommendations with built-in options and custom query examples
docs-mslearn/toolkit/hubs/template.md	Added three new parameters for recommendations: enableRecommendations, enableAHBRecommendations, enableSpotRecommendations; added prettier-ignore comments for formatting
docs-mslearn/toolkit/changelog.md	Added changelog entry for recommendations feature under vNext; updated markdown lint directives
docs-mslearn/TOC.yml	Added "Configure recommendations" page to navigation between "Configure scopes" and "Configure dashboards"
docs-mslearn/best-practices/storage.md	Enhanced unattached disks section with cross-reference to recommendations feature and improved structure
docs-mslearn/best-practices/networking.md	Added cross-references to recommendations feature for idle application gateways, load balancers, and public IP addresses
docs-mslearn/best-practices/general.md	Added new Azure Advisor section with query and cross-reference to recommendations feature
docs-mslearn/best-practices/databases.md	Enhanced unused Elastic Pools section with cross-reference to recommendations feature
docs-mslearn/best-practices/compute.md	Added comprehensive sections for Spot VMs, Azure Hybrid Benefit for Windows and SQL VMs with cross-references to recommendations feature