Mark "Settings" and "Nuance" as launchable applications

Summary:
Fixes T12790. I don't think this was actually a regression, Settings just wasn't launchable before global settings (since it had no real landing page, and the profile menu always had a link) and didn't get marked launchable once we added them.

I also double-checked other un-launchable apps; Nuance is probably close enough to make launchable now while I'm in here.

Test Plan: Typed "settings" into global typeahead, got settings.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12790

Differential Revision: https://secure.phabricator.com/D18062