Update StyleEngine and StyleSheet to incorporate AngleSharp Html elements

[Jayx239]

What is your proposed enhancement? What would you like to be enhanced? What functionality are you looking for? Add the IElement to StyleSheet containing AngleSharp object for external style link elements. Update StyleEngine to support this functionality. Why do you want this enhancement? Describe the need for this enhancement It would be helpful for integrating AngleSharp functionality into BrowseSharp more effectively. How would you recommend this enhancement be implemented? Give a technical description of what could be done to implement this enhancement (optional) Update StyleEngine and StyleSheet.