Fix shared exaples bad naming

[eleidan]

Rename unauthorized into unauthenticated, and create unauthorized. Previous commit introduces changes in shared examples naming, along with new shared examples. Originally, the unauthorized was chosen after status code 401 naming. When another shared example was introduced to represent authorization issue it appeared that shared examples' names should represent their true meaning. As a result, shared examples in subject must be treated as follows:

• unauthenticated -- user must pass login/password check, that is, to log into system;
• unauthorized -- user must have appropriate privileges along with logging into system.

@alazarchuk , @epmlys , @rubycop , @afurm

[afurm]

+

[epmlys]

+1