Lots of code refactoring to use XAML behaviors instead of code-behind

New Save button in the AppBar
EntryPage now uses the same AppBar as GroupPage (but not shared...)
Some new Symbol mappings

ModernKeePass/ViewModels/RecentVm.cs

@@ -36,6 +36,7 @@ namespace ModernKeePass.ViewModels
 
         public RecentVm()
         {
+            // TODO: opening the files actually changes the MRU order
             var mru = StorageApplicationPermissions.MostRecentlyUsedList;
             foreach (var entry in mru.Entries)
             {