Refactor the friend namespace (#721)

* Refactor the friend namespace and UInt128

This commit also:
- Fix GetFriendsList arguments ordering.
- Add GetFriendListIds.
- Expose the permission level of the port instance.
- InvalidUUID => InvalidArgument

* friend: add all cmds as commments

* add Friend structure layout

* Rename FriendErr to FriendError

* Accurately implement INotificationService

* Fix singleton lock of NotificationEventHandler

* Address comments

* Add comments for IDaemonSuspendSessionService cmds

* Explicitly define the Charset when needed

Also make "Nickname" a string

* Address gdk's comments

Ryujinx.HLE/HOS/Services/ServiceFactory.cs

@@ -100,10 +100,19 @@ namespace Ryujinx.HLE.HOS.Services
                     return new IeTicketService();
 
                 case "friend:a":
-                    return new Friend.IServiceCreator();
+                    return new Friend.IServiceCreator(Friend.FriendServicePermissionLevel.Admin);
 
                 case "friend:u":
-                    return new Friend.IServiceCreator();
+                    return new Friend.IServiceCreator(Friend.FriendServicePermissionLevel.User);
+
+                case "friend:v":
+                    return new Friend.IServiceCreator(Friend.FriendServicePermissionLevel.Overlay);
+
+                case "friend:m":
+                    return new Friend.IServiceCreator(Friend.FriendServicePermissionLevel.Manager);
+
+                case "friend:s":
+                    return new Friend.IServiceCreator(Friend.FriendServicePermissionLevel.System);
 
                 case "fsp-srv":
                     return new IFileSystemProxy();