audio: Rewrite SoundIo bindings (#4088)

* audio: Rewrite SoundIo bindings

This rewrite SoundIo bindings to be safer and not a pedantic autogenerated mess.

* Address comments

* Switch DllImport to LibraryImport

* Address gdkchan's comment

Ryujinx.Audio.Backends.SoundIo/Native/SoundIoBackend.cs

@@ -0,0 +1,13 @@
+namespace Ryujinx.Audio.Backends.SoundIo.Native
+{
+    public enum SoundIoBackend : int
+    {
+        None = 0,
+        Jack = 1,
+        PulseAudio = 2,
+        Alsa = 3,
+        CoreAudio = 4,
+        Wasapi = 5,
+        Dummy = 6
+    }
+}