Hi!
1. Go to admin mode -> Config tab.
2. Click on Plug-in manager.
3. Select the overview tab.
4. Find any of the links to "EPiServer.WorkflowFoundation.UI" and click on it.
5. Click on the overview tab, unckeck the "Workflow (EditPanel)" check box (and any other workroom-related plugins you want to deactivate) and press save.
The workroom plug-ins should no longer be visible.