title: Swift Document Picker Directory URL
body: <p>I implemented the UI Document Picker to select files from iCloud Drive, local storage etc. and it all works fine so far.
  As we all know it is possible to also select files from apps like Dropbox, OneDrive etc. but for a user who does not know this is possible, the document picker can be quite confusing.</p>
  <p><strong>Is it possible to implement a button to directly open the Dropbox Folder (or any other), instead of having to navigate trough the document directorys?</strong></p>
  <p>Apple provides a functionality like directoryURL but im not sure if this works, especially if a user might not have installed an app like Dropbox or so.
  I don't want to navigate to another app or use frameworks for this. I just want to programmatically change the starting point when opening the Document Picker to show files of external apps. It would be nice if it is also possible to check if an app is available/installed so that a button can be shown or not depending on that.</p>
  <p><a href="https://i.stack.imgur.com/W3nrr.png" rel="nofollow noreferrer">Picture: Storages of external apps accessible with document picker</a></p>