Make unused settings in browser bookmark plugin functional or remove them

These settings in the browser bookmark plugin are unused

```C#
public class Settings : BaseModel
{
public bool OpenInNewBrowserWindow { get; set; } = true;

public string BrowserPath { get; set; }
```

They don't appear in the UI and aren't considered when opening a bookmark

They should either be removed or made functional

BrowserPath is presumably intended to control which browser opens it - tbh its likely most people would want it to match the one the bookmark came from so maybe that would require a more complex solution instead of just making this exact setting functional as is. Such a feature is requested in #2805

The OpenInNewBrowserWindow setting should be easier to get working as we already support something similar in the url plugin