Prompt for confirmation when a user deletes a document locally

(timebox) As a user, when deleting one or more file, I can see a confirmation dialog

Mockups : 

https://nuxeo.invisionapp.com/freehand/document/zURrCAp2C

if delete serverside mode :

Do you really want to delete xx for all users ?

> don't ask me again > see sync options > cancel > delete for everyone

If unsync mode : 

"document" will be deleted from your device, but other member will still have access. You can change deletion behavior in settings.
> Don't ask me again > cancel > delete anyway

• Improve awareness of what will happen server side , with dialog with a “cancel” option (the folder or file is actually moved to trash first, cancel will restore them).
• Explicitly propose to user to unsync instead of deleting for everyone
• A “don’t ask me again” is a very simple way to ask user how he want deletions to be handled
• Access in settings how deletions are handled (delete on server, unsync (default))