Revise Fine Tuning Scenarios and Techniques

[skytin1004]

Purpose

This pull request updates and clarifies the documentation for fine-tuning scenarios across Microsoft Foundry and Azure environments. It enhances explanations of platform, infrastructure, and tooling layers; modernizes references to supported model families; and introduces a more accurate comparison table for fine-tuning techniques.
These changes improve clarity, correctness, and usability for developers adapting Microsoft Phi models.

Description

• Simplified the Platform section by removing references to tools that are not directly covered in this documentation. The section now uses more general terminology aligned with the scope of the content.
• Removed incorrect placeholder text such as [Insert icons for ONNX Runtime and ONNX Runtime] from the Tools & Frameworks section.
• Revised Platform, Infrastructure, and Tools & Frameworks sections for improved accuracy and modern terminology.
• Updated branding references from Azure AI Foundry to Microsoft Foundry.
• Clarified compute options for fine-tuning, including GPU and CPU usage.
• Updated serverless fine-tuning availability to reflect support for Phi-3, Phi-3.5, and Phi-4 model families.
• Replaced the previous fine-tuning scenario table with a new Fine-Tuning Techniques Comparison table for improved technical correctness.
• Ensured consistent descriptions across LoRA, QLoRA, PEFT, DeepSpeed, ZeRO, and DoRA.
• Improved overall structure, readability, and consistency of the documentation page.

Does this introduce a breaking change?

When developers merge from main and run the server, azd up, or azd deploy, will this produce an error?
If you're not sure, try it out on an old environment.

[ ] Yes
[x] No

Does this require changes to learn.microsoft.com docs?

This repository is referenced by (https://azure.microsoft.com/products/phi-3)
which includes deployment, settings and usage instructions.

[ ] Yes
[x] No

Type of change

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

Fixes #471

[skytin1004]

Hi @leestott, I've opened a documentation update PR for the fine-tuning section.
Whenever you have time, I'd appreciate your feedback.