Config unification

Replace Candlepin's Config class with Configuration from common. No more ```new Config()``` in mainline code, rely on injection of Configuration from Guice.

TEST
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Simply do what you normally do to use Candlepin.

NOTE: I did not update Gutterball.
We probably shouldn't use "candlepin" prefixed keys here since Gutterball will be using this code as well.  Maybe when the ConfigurationParser gets created we could pass in the project name as a parameter and use that value as a prefix.