Federated recipe and whisper-clean.py script

From issue #44:
* Added a **federated** application **recipe** example (2942ed1).
* Added bats **tests** for federated recipes (7668dbd).
* Added **whisper-clean** helper script (8a3a45f).
 * whisper-clean-this-node.sh script (c524d76).

Bonus:
* Force `relay-rules.conf` file creation to avoid *No such file or directory* error (9f3a2de).
* `graphite-web` attributes moved to *default.rb* due to attribute dependecy (b90b208).