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/Pctl/IParentalControlServiceFactory.cs

@@ -10,20 +10,20 @@ namespace Ryujinx.HLE.HOS.Services.Pctl
 
         [Command(0)]
         // CreateService(u64, pid) -> object<nn::pctl::detail::ipc::IParentalControlService>
-        public long CreateService(ServiceCtx context)
+        public ResultCode CreateService(ServiceCtx context)
         {
             MakeObject(context, new IParentalControlService());
 
-            return 0;
+            return ResultCode.Success;
         }
 
         [Command(1)] // 4.0.0+
         // CreateServiceWithoutInitialize(u64, pid) -> object<nn::pctl::detail::ipc::IParentalControlService>
-        public long CreateServiceWithoutInitialize(ServiceCtx context)
+        public ResultCode CreateServiceWithoutInitialize(ServiceCtx context)
         {
             MakeObject(context, new IParentalControlService(false));
 
-            return 0;
+            return ResultCode.Success;
         }
     }
 }