Bye bye workspace screens table

Removing a separate table for workspace screens. List of screens are
automatically parsed using the items in the favorites DB. Order of the
screen based on the screen id and rearranging screens is no longer
supported. In case the screens need to be rearranged, all the items
in the favorites db will need to be updated with new screen ids.

This makes backing up the DB (in the same database) easier as only
one table needs to be duplicates.

Change-Id: I8ba947a898f637d780e2f49925e78604263126e8