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
---------
Simply do what you normally do to use Candlepin.

NOTE: I did not update Gutterball.
Can we make `merge` into a static method on the implementation classes?

Something like

```java
public static Configuration merge(Configuration ... configs) {
        MapConfiguration mergedConfig = new MapConfiguration();
        for (Configuration c : configs) {
            for (String key : c.getKeys()) {
                if (!mergedConfig.containsKey(key)) {
                    mergedConfig.setProperty(key, c.getProperty(key));
                }
            }
        }
        return mergedConfig;
}
```

That way each configuration would be trumped by the one following it.