Refactoring result codes (#731)

* refactoring result codes

- Add a main enum who can handle some orphalin result codes and the default `ResultCode.Success` one.
- Add sub-enum by services when it's needed.
- Remove some empty line.
- Recast all service calls to ResultCode.
- Remove some unneeded static declaration.
- Delete unused `NvHelper` class.

* NvResult is back

* Fix

Ryujinx.HLE/HOS/Services/Aud/AudioRenderer/MemoryPoolIn.cs

@@ -11,4 +11,4 @@ namespace Ryujinx.HLE.HOS.Services.Aud.AudioRenderer
         public int             Unknown14;
         public long            Unknown18;
     }
-}
+}