[WIP] Introduce Microsoft.Extensions.AI to AIPlatform

[Krzysztof318]

This is initial PR, its purpose is implement IChatClient from Microsoft.Extensions.AI.Abstractions LINK.

Before I jump into writing the implementation, please give me feedback on whether my approach is good for your repository.
Is the project location okay? Where can I add the unit tests?

@stephentoub I will glad to you if you also give me some help with this PR.

[jskeet]

It would be better to file an issue about what you want to achieve first, IMO. Personally I would prefer there to be another package that depends on both the existing AI Platform package and Microsoft.Extensions.AI to bridge the two, rather than adding a dependency directly - but @amanda-tarafa may have alternative suggestions.

[stephentoub]

I will glad to you if you also give me some help with this PR.

I'll be glad to help.

[amanda-tarafa]

@Krzysztof318 do please file an issue explaining what your goal is, if there are alternatives to achieving that goal that you have discarded, etc. For instance, same as @jskeet I'd prefer a completely separate package, but we should discuss that.

Equally, we'd need to discuss internally about ongoing maintenance, etc. and accept (or not) the work accordingly.

It's better to have all those discussions in an issue that in PRs. You can then use PRs to demonstrate or support some of the technical decisions being discussed.

Thanks!

[Krzysztof318]

@amanda-tarafa @jskeet Okay I will post issue tommorow

[Krzysztof318]

I created an issue #13815 and I leave this PR for future concept purposes.