Cleanups: Getcourse

This PR removes the old GC recipes. *I recommend to first merge the current status in stable, then merge this PR* - this PR removes fallback for the old mechanism if I have introduced some bug in the deploy flow.

* removed no longer used getcourse recipes
* Cleanups:
 * renamed `getcourse-deploy` to `getcourse_deploy` since all others attrs are using underscores
 * no longer hardcoded path and testname for frontend_acceptance tests
 * commented api.rb
 * sane defaults for all params in defaults.rb

The relocated `travis_token` is already updated in Opsworks (both old and new currently exist)