Refactoring uos initializer

Here we've done many changes on how the UOS is initialized.

* All components follows a 4 stage (creation, initialization, start, stop) lifecycle controlled by the UOSComponent interface.
* UOSApplicationContext was renamed to UOS in an effort to make it more clear that initializing this class starts the middleware itself.
* UOS contains a main() method that allows to run the middleware out of the box.
* Logger was left as an java.util.Logging class.