Config properties

Remove the use of default.properties in favor of using a static class, ```ConfigProperties```, like we did in Candlepin. This allows defining things as constants and letting the compiler deal with typos. Also added the ability for Gutterball to read ```/etc/gutterball/gutterball.conf```. We still need to add the auto generation stuff from Candlepin but at least you can override things now. 

This commit updates things in both common and gutterball. I added a test for the ContextListener but the initialized portion had to be ignored at the moment.
I believe that is an artifact of the new config used. We can probably get rid of the using the default value on gets now. ConfigProperties should have the defaults for us.