XWIKI-7947: Attaching a file after a rollback restores previous attachments
* Add a DocumentReferenceResolver that creates a DocumentReference from a path string "wiki/space/page"
* Don't keep the DocumentReference in DeletedFilesystemAttachment. Get it from the XWikiAttachment object.
* Remove code duplicated by the DeletedFilesystemAttachment constructor.
* When getting a deleted attachment from FilesystemAttachmentRecycleBinStore make sure it is bound to the associated document because otherwise it cannot be restored.