IPC services refactoring (#726)

* IPC services refactoring

- Use custom Attributes to handle services.
- Add a way to set the permissions and fix the bsd service to use it.
- Little cleanup.
- C#7.1 is required.

* fix var name

* fix syntax

* Change Permission to Parameter

* Delete BsdServicePermissionLevel.cs

* Fix Linq

Ryujinx.HLE/HOS/Services/Time/IStaticService.cs

@@ -5,6 +5,9 @@ using System.Collections.Generic;
 
 namespace Ryujinx.HLE.HOS.Services.Time
 {
+    [Service("time:a")]
+    [Service("time:s")]
+    [Service("time:u")]
     class IStaticService : IpcService
     {
         private int _timeSharedMemoryNativeHandle = 0;
@@ -15,7 +18,7 @@ namespace Ryujinx.HLE.HOS.Services.Time
 
         private static readonly DateTime StartupDate = DateTime.UtcNow;
 
-        public IStaticService()
+        public IStaticService(ServiceCtx context)
         {
             _commands = new Dictionary<int, ServiceProcessRequest>
             {