#21918 Now supports launching apps which do not have an engine.
- Also changed the logic how items appear on menus for different
operating systems: now, items will appear whereever they have been
defined with a path in the settings, rather than depending on if they
are supported or not by the launcher. This makes it possible for a
studio to correctly control the options for launch, for example if they
don't have maya installed for windows, it wont show up, whereas it
previously would.