Implement backup and restore functionality; add IBackupService and BackupService; refactor services to use DbContextFactory

src/Duempelkas.App/Components/Layout/MainLayout.razor

@@ -1,4 +1,5 @@
 @inherits LayoutComponentBase
+@using System.Reflection
 
 <div class="d-flex flex-column vh-100">
     <nav class="app-navbar d-flex justify-content-between align-items-center">
@@ -43,10 +44,17 @@
     {
         get
         {
-            var now = DateTime.Now;
-            var yearShort = now.Year % 100;
-            var dayOfYear = now.DayOfYear;
-            return $"{yearShort}.{dayOfYear}";
+            var entryAssembly = Assembly.GetEntryAssembly();
+            var infoVersion = entryAssembly?
+                .GetCustomAttribute<AssemblyInformationalVersionAttribute>()?
+                .InformationalVersion;
+
+            if (!string.IsNullOrWhiteSpace(infoVersion))
+            {
+                return infoVersion.Split('+')[0];
+            }
+
+            return entryAssembly?.GetName().Version?.ToString(2) ?? "1.0";
         }
     }
 }