Add MAUI csharp\sample\InferenceSample\ project

[skottmckay]

Description:
Add a MAUI variant to the InferenceSample setup so we have an equivalent setup for MAUI as for the other platforms.

This provides a setup to do some basic local testing of using an InferenceSession in a MAUI app.

Intended usage is an ORT developer who is making changes to the C# project, as that project is referenced directly (i.e. the ORT nuget packages are not used). 'InferenceSample' isn't a great name given that - will look at changing in a separate PR.

Motivation and Context
Provide way to do local testing for a MAUI app.

[snnn]

Would you consider putting it in https://github.com/Microsoft/onnxruntime-inference-examples ? Then you don't need to run so many pipelines and they will have much fewer compliance requirements.

[skottmckay]

Would you consider putting it in https://github.com/Microsoft/onnxruntime-inference-examples ? Then you don't need to run so many pipelines and they will have much fewer compliance requirements.

I have a PR for a 'real' example app there. microsoft/onnxruntime-inference-examples#128

That uses the official nuget packages and is a more complete example.

This is just a very simple one for developer testing, which uses the csproj (i.e. can only be run if you have the ORT source) and not the nuget packages.

For example, say you change something about the Android setup. With this local project you can test without having to create a nuget package which is insanely complicated to do correctly for the native libraries.