C# bindings (#650)

* First workin version of the C# bindings

* Update README.md

Signed-off-by: mvenditto <venditto.matteo@gmail.com>

* Added more docs + fixed prompt callback signature

* build scripts revision

* Added .editorconfig + fixed style issues

---------

Signed-off-by: mvenditto <venditto.matteo@gmail.com>

gpt4all-bindings/csharp/Gpt4All.Samples/Program.cs

@@ -0,0 +1,21 @@
+using Gpt4All;
+
+var modelFactory = new Gpt4AllModelFactory();
+
+var modelPath = args[0];
+
+using var model = modelFactory.LoadModel(modelPath);
+
+var input = args.Length > 1 ? args[1] : "Name 3 colors.";
+
+var result = await model.GetStreamingPredictionAsync(
+    input,
+    PredictRequestOptions.Defaults);
+
+await foreach (var token in result.GetPredictionStreamingAsync())
+{
+    Console.Write(token);
+}
+
+Console.WriteLine();
+Console.WriteLine("DONE.");