[HLE] Renamed INotificationServicesForSystem and implemented a few commands and stubs (#6)

Should allow Ring Fit and other games that rely heavily on the notification system to get in-game (?), needs testing.

if you're wondering what happened to the first branch -- no you're not. (duplicated history somehow??)

Reviewed-on: https://git.ryujinx.app/projects/Ryubing/pulls/6

src/Ryujinx.Common/Logging/LogClass.cs

@@ -51,6 +51,7 @@ namespace Ryujinx.Common.Logging
         ServiceNgct,
         ServiceNifm,
         ServiceNim,
+        ServiceNotification,
         ServiceNs,
         ServiceNsd,
         ServiceNtc,