[FEATURE] Enable support for shared folders in iCloud drive

[mandarons]

Use case
As a user, I want to download iCloud shared folders so that I can always have backup of shared folders as well.

Describe the solution you'd like
The app should download shared folders (folders shared by the user and another user) as if they are regular folders.

Describe alternatives you've considered
None available.

Additional context
Apple introduced Shared Folders feature in iCloud Drive.