Implementing Recent Files WIP

Code refactoring
Entry coloring

ModernKeePass/ViewModels/RecentVm.cs

@@ -0,0 +1,18 @@
+using ModernKeePass.Models;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+
+namespace ModernKeePass.ViewModels
+{
+    public class RecentVm : INotifyPropertyChanged
+    {
+        public ObservableCollection<RecentItem> RecentItems { get; set; }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        public void NotifyPropertyChanged(string propertyName)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}