add solution without dependencies on example projects

[james-s-tayler]

Addresses https://github.com/saddam213/OnnxStack/issues/12

In practice might be nicer to have the solution file that contains the core project and the support for specific ONNX models be the project named OnnxStack.sln and the one that contains the example usage applications be something like Examples.sln. I'm guessing it's all in one single solution as that's the easiest in terms of work flow as you can directly reference the library code inside the UI projects without having to go through the process of compiling it and building a NuGet package, and then adding that NuGet package into the sample apps as you work. Though, no reason the Examples.sln couldn't also contain all the things, it's just it would feel slightly clearer if the core library and support for models were the thing named OnnxStack.sln, but that's just my 2c.

[saddam213]

Thanks for the Pull request

Yeah the addition of the WPF project last week most likely broke some stuff as its the only project that is not cross platform

However adding a solution file just for the projects that have nugets is a perfect solution.

Thanks for the PR :)