Added CORS configuration to puppet-storyboard

Storyboard will soon support CORS, which is configured via
storyboard.conf. This patch adds the two relevant properties
to the puppet module, and makes them accessible in
storyboard::application.

Depends on https://review.openstack.org/#/c/124163/

Change-Id: I33a33076a18a9192b067a9f6f08d752ff8c22e3b