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/IParentalControlService.cs

@@ -15,7 +15,7 @@ namespace Ryujinx.HLE.HOS.Services.Pctl
 
         [Command(1)] // 4.0.0+
         // Initialize()
-        public long Initialize(ServiceCtx context)
+        public ResultCode Initialize(ServiceCtx context)
         {
             if (_needInitialize && !_initialized)
             {
@@ -26,16 +26,16 @@ namespace Ryujinx.HLE.HOS.Services.Pctl
                 Logger.PrintWarning(LogClass.ServicePctl, "Service is already initialized!");
             }
 
-            return 0;
+            return ResultCode.Success;
         }
 
         [Command(1001)]
         // CheckFreeCommunicationPermission()
-        public long CheckFreeCommunicationPermission(ServiceCtx context)
+        public ResultCode CheckFreeCommunicationPermission(ServiceCtx context)
         {
             Logger.PrintStub(LogClass.ServicePctl);
 
-            return 0;
+            return ResultCode.Success;
         }
     }
 }