Always store UTIs for include/exclude types in FieSystemObjectSources (supersedes #1681)

See #1681 for more of the discussion

Instead of fiddling with UTIs in the `QSDirectoryScanner`, I think it's much more wise to just *always* store the UTI for the include/exclude types option (be it `dyn-xxx` or not)
This has some fancy benefits of being able to show the nice name for OSTypes (e.g. if you enter `'fold'` you'll see `folder` in the token, instead of `'fold'` like it used to be, and also you can see the UTI from the popup of the menu item (just like I've done for the bundle ID for trigger scope)