Move Logger and Debugger to the common/util folder

There's been discussion about sharing utilities across the DevTools and Agent folder. This is already partially done with the libraries, but it'll be further done now that there's a common/util folder. 

The next step will be to replace all of the debug usage with Logger as that's far superior.

Also, I'd like to move lib into common as that's also shared between projects.

Lastly, I'd like to change DevTools to Inspector cause that's the word we use.