environs: remove Name method from environs.Environ

This change removes the `Name` method from the `Environ` interface.

The rational for this comes from the work at the Identity sprint which has identified that the canonical identifier for an environment is its UUID. This downplays the importance of the `Environ.Name()` method, so the method has been removed and replaced by the same method available on `Environ.Config()`. As these _MUST_ be the same, the effect on the caller is nil.

It should be noted that this change identified several places where `Environ.Name()` and `Environ.Config().Name()` were not reporting the same values and these have been fixed.