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/Ns/IServiceGetterInterface.cs

@@ -3,13 +3,15 @@ using System.Collections.Generic;
 
 namespace Ryujinx.HLE.HOS.Services.Ns
 {
+    [Service("ns:am2")]
+    [Service("ns:ec")]
     class IServiceGetterInterface : IpcService
     {
         private Dictionary<int, ServiceProcessRequest> _commands;
 
         public override IReadOnlyDictionary<int, ServiceProcessRequest> Commands => _commands;
 
-        public IServiceGetterInterface()
+        public IServiceGetterInterface(ServiceCtx context)
         {
             _commands = new Dictionary<int, ServiceProcessRequest>
             {
@@ -19,7 +21,7 @@ namespace Ryujinx.HLE.HOS.Services.Ns
 
         public long GetApplicationManagerInterface(ServiceCtx context)
         {
-            MakeObject(context, new IApplicationManagerInterface());
+            MakeObject(context, new IApplicationManagerInterface(context));
 
             return 0;
         }