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.
Actually, in my previous comment I think instead of 

```java
public static Configuration merge...
```

it should be

```java
public static MapConfiguration merge...
```

Or whatever the implementation class is.  That way the caller can elect to keep it as the implementation class or they can just up-cast to Configuration if they want.  If it just returned Configuration, the caller might have to down-cast.