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/Services/Account/Acc/AccountManager.cs

@@ -0,0 +1,74 @@
+using Ryujinx.Common;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Ryujinx.HLE.HOS.Services.Account.Acc
+{
+    public class AccountManager
+    {
+        private ConcurrentDictionary<string, UserProfile> _profiles;
+
+        public UserProfile LastOpenedUser { get; private set; }
+
+        public AccountManager()
+        {
+            _profiles = new ConcurrentDictionary<string, UserProfile>();
+
+            UserId defaultUserId    = new UserId("00000000000000010000000000000000");
+            byte[] defaultUserImage = EmbeddedResources.Read("Ryujinx.HLE/HOS/Services/Account/Acc/DefaultUserImage.jpg");
+
+            AddUser(defaultUserId, "Player", defaultUserImage);
+            
+            OpenUser(defaultUserId);
+        }
+
+        public void AddUser(UserId userId, string name, byte[] image)
+        {
+            UserProfile profile = new UserProfile(userId, name, image);
+
+            _profiles.AddOrUpdate(userId.ToString(), profile, (key, old) => profile);
+        }
+
+        public void OpenUser(UserId userId)
+        {
+            if (_profiles.TryGetValue(userId.ToString(), out UserProfile profile))
+            {
+                (LastOpenedUser = profile).AccountState = AccountState.Open;
+            }
+        }
+
+        public void CloseUser(UserId userId)
+        {
+            if (_profiles.TryGetValue(userId.ToString(), out UserProfile profile))
+            {
+                profile.AccountState = AccountState.Closed;
+            }
+        }
+
+        public int GetUserCount()
+        {
+            return _profiles.Count;
+        }
+
+        internal bool TryGetUser(UserId userId, out UserProfile profile)
+        {
+            return _profiles.TryGetValue(userId.ToString(), out profile);
+        }
+
+        internal IEnumerable<UserProfile> GetAllUsers()
+        {
+            return _profiles.Values;
+        }
+
+        internal IEnumerable<UserProfile> GetOpenedUsers()
+        {
+            return _profiles.Values.Where(x => x.AccountState == AccountState.Open);
+        }
+
+        internal UserProfile GetFirst()
+        {
+            return _profiles.First().Value;
+        }
+    }
+}