Add support for storing photos and videos without using the FileSavePicker

[jeromelaban]

What would you like to be added

Add support for WinUI APIs such as KnownFolders.GetFolderAsync that would provide access to saving files directly.

Why is this needed

Once the permission has been provided, it gives a better user experience that having to go through the picker.

For which platform

Android, iOS

Anything else we need to know?

No response