Refactor Hosted and Private Chef to the new Enterprise Chef naming

Opscode has renamed Hosted and Private Chef flavors into a single Enterprise Chef one. Both products have been joined into a single one, which can be downloaded or used hosted.

Jclouds should reflect the new naming and join the two providers into a single one, to be aligned with the new naming. The api hasn't changed, so it should only be a matter of renaming the provider and joining both APIs into a single one.