allow setting vault url for environment

src/App/Abstractions/Services/IAppSettingsService.cs

@@ -11,6 +11,7 @@ namespace Bit.App.Abstractions
         bool AutofillPasswordField { get; set; }
         string SecurityStamp { get; set; }
         string BaseUrl { get; set; }
+        string VaultUrl { get; set; }
         string ApiUrl { get; set; }
         string IdentityUrl { get; set; }
     }