onnxruntime

7e6331d5 - Add ability to register custom ops from ORT extensions nuget package (#15696)

Add ability to register custom ops from ORT extensions nuget package (#15696) ### Description <!-- Describe your changes. --> Add infrastructure so it's easy for a user to add the ORT extensions nuget package and register the custom ops for C# apps. ### Motivation and Context <!-- - Why is this change required? What problem does it solve? - If it fixes an open issue, please link to the issue here. --> Need to be able to use extensions on mobile platforms with Xamarin/MAUI