Add new Phi-4 Onnx multi-modal project in C#

[elbruno]

Purpose

The changes include updates to the documentation and code files related to the Phi labs using C#. The csharplabs.md and readme.md files were enhanced with clearer instructions and additional project descriptions. A new project for multi-modal image processing was added (LabsPhi4-MultiModal-01Images.csproj), which utilizes ONNX models for image analysis. The Program.cs file was modified to implement image processing and generate responses based on user prompts. Additionally, the project structure in the solution file (LabsPhi.sln) was updated to include the new multi-modal project, ensuring proper configuration for building and running within the solution.

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)
[ ] Documentation content changes
[X] Other... Please describe: new Multi Modal Sample in C# using Onnx