GuestLog - User message improvements

- Added UserMessageService to have common methods for showing messages and errors to the user.
- Added Result record so services can return status on operation error (so it can be shown in the UI messages).
- Updated services to use the new Result record.
- Updated pages to use the new IUserMessageService.

src/Somnia.GuestLog/Program.cs

@@ -59,6 +59,8 @@ builder.Services.AddSingleton<IGuestDocumentService, GuestDocumentService>();
 builder.Services.AddSingleton<IStayEntryService, StayEntryService>();
 builder.Services.AddSingleton<IDataListService, StaticDataListService>();
 
+builder.Services.AddScoped<IUserMessageService, UserMessageService>();
+
 // Add Factories (and it's services)
 builder.Services.AddFactoryDI<IAddressQueryFactory, ConfigFileAddressQueryFactory>();