You are looking for the wrong Library folder. When you open your hard drive, you’ll see four folders; Applications, Library, System and Users. This is the Library folder you should use.
Actually there is a VST folder in your “User” library aswell. But this is very rarely used.
In their infinite wisdom to make life as difficult as possible for their users, Apple has decided to hide the User Library. To get to it, go to the “Go” menu and press the [Option] key. Now it will magically appear in the menu.
Do not mess about in the Cubase 8 package, unless you know what you’re doing.
EDIT
I didn’t know what QL Spaces was, so I looked it up. As far as I can tell it’s not a VST effect at all! It runs withing the OL Play VSTi. If I am correct, this is what you should be looking for. Check the instrument menu for an Instrument Track.