Enhancement: added drag-drop property

In order to enable file moving via drag & drop we added 
the property drag-drop on OcTable and OcTableFiles

https://github.com/owncloud/web/issues/5592
https://github.com/owncloud/owncloud-design-system/pull/1539
https://github.com/owncloud/owncloud-design-system/pull/1562
https://github.com/owncloud/owncloud-design-system/pull/1574