Persist WebView states

[Slion]

How can I persist the state of the WebView using WinUI? On Android they have those saveState and restoreState methods for instance.
Basically I want to save the state of the WebView to be able to restore it next time the user starts the application.

I went through the APIs but did not find anything that would let you do that. It's a pity cause being able to resume where you left off after restarting your app is an essential functionality and apparently missing from WebView2.

Also asked on StackOverflow. Apparently that's not possible to date which is very disappointing and a major oversight from Microsoft.

See #4713.