nswag-portable

This project builds NSwag in self-contained mode, so it could be used without installing .NET.

Notice, that we build NSwag and NJsonSchema from NON-OFFICIAL repositories:

• NSwag: https://github.com/mccsoft/NSwag
• NJsonSchema: https://github.com/mccsoft/NJsonSchema

These repositories contains fixes for:

• Correct handling of OneOf statements (when there are more than one of them).
• Handling of JSON-serialized Query parameters (https://swagger.io/docs/specification/describing-parameters/#schema-vs-content)