public static OptionsBuilder <TOptions> AddAdminSiteOptions
 <TOptions>(this OptionsBuilder <TOptions> optionsBuilder,
            Action <TOptions>?configureAdminOptions = null)
     where TOptions : SharePointSiteAuthorizationOptions =>
 optionsBuilder.AddNestedNamedOptions(
     SharePointSiteAuthorizationOptions.AdminSiteOptionsName,
     configureAdminOptions,
     GetAdminUrlFromSiteUrl
     );