feat: selected realm stored in browser's local storage

WotBlitzStatisticsPro.Blazor/Services/ILocalStorageService.cs

@@ -1,4 +1,5 @@
 using System.Threading.Tasks;
+using WotBlitzStatisticsPro.Blazor.Model;
 
 namespace WotBlitzStatisticsPro.Blazor.Services
 {
@@ -7,5 +8,7 @@ namespace WotBlitzStatisticsPro.Blazor.Services
         Task SetItemAsync<T>(string key, T item);
 
         Task<T> GetItemAsync<T>(string key);
+
+        Task<UserSettings> ReadSettings();
     }
 }