Moved config.js file into app.js to move items out of window scope

Best practices say to keep elements out of the window scope - while working with mean.io, I noticed that all elements under the app.js and config.js files are attached to the window by default. I refactored this so that the config information is now in app.js and deleted config.js. This allows us to keep things out of window scope. 

I've done a few projects in Angular so far, but without mean.io so I'm new to the seed. If I'm missing a convention or something else, please let me know!