Initial commit of common library cookbook

Contains common library routines and recipes that
all other OpenStack service cookbooks use, including
routines for finding endpoints, passwords, roles,
and building URIs.

Contains a default recipe that sets up the APT
repository locations as well as ChefSpec tests
that cover the cookbook code.

This is designed for the Grizzly packages of OpenStack.

Change-Id: I2f33339418742f7f64cc848d14ad481b45811795