Cameos, a video app from Google that lets celebrities answer questions about themselves — and shares a similar name to a Chicago breakout consumer startup — is shutting down. Google said in an email to participants that it's shuttering its Cameos app on Feb. 17, and existing videos posted via the app will no longer be shown on Google. Google said it "learned a lot" from the invite-only pilot it launched nearly four years ago, but it will be "focusing efforts on other content creation projects."…