Refactoring HOS folder structure (#771)

* Refactoring HOS folder structure

Refactoring HOS folder structure:

- Added some subfolders when needed (Following structure decided in private).
- Added some `Types` folders when needed.
- Little cleanup here and there.
- Add services placeholders for every HOS services (close #766 and #753).

* Remove Types namespaces

Ryujinx.HLE/HOS/Services/Audio/ResultCode.cs

@@ -0,0 +1,15 @@
+namespace Ryujinx.HLE.HOS.Services.Audio
+{
+    enum ResultCode
+    {
+        ModuleId       = 153,
+        ErrorCodeShift = 9,
+
+        Success = 0,
+
+        DeviceNotFound        = (1 << ErrorCodeShift) | ModuleId,
+        UnsupportedRevision   = (2 << ErrorCodeShift) | ModuleId,
+        UnsupportedSampleRate = (3 << ErrorCodeShift) | ModuleId,
+        OpusInvalidInput      = (6 << ErrorCodeShift) | ModuleId
+    }
+}