account: Adds AccountManager (#2184)

* account: Adds Account Manager

In a way to have Custom User Profiles merged in master faster, this PR adds a `AccountManager` class (based on `AccountUtils` class) and the following changes have been made:
- Adds a "default profile values" which were the old hardcoded ones.
- The image profile is moved to the Account service folder.
- The hardcoded UserId for the savedata is now using the `AccountManager` last opened one.
- The DeviceId in Mii service is changed to the right value (checked by REd sys:set call).

* Fix csproj

* Addresses gdkchan's comments

* Fix UserProfile fields

* Fix mii GetDeviceId()

* Update Ryujinx.HLE.csproj

Ryujinx.HLE/HOS/ApplicationLoader.cs

@@ -648,7 +648,7 @@ namespace Ryujinx.HLE.HOS
         {
             Logger.Info?.Print(LogClass.Application, "Ensuring required savedata exists.");
 
-            Uid user = _device.System.State.Account.LastOpenedUser.UserId.ToLibHacUid();
+            Uid user = _device.System.AccountManager.LastOpenedUser.UserId.ToLibHacUid();
 
             ref ApplicationControlProperty control = ref ControlData.Value;