Do not derive objects from ProfitBricksService
Do not derive objects from ProfitBricksService

The objects Datacenter, FirewallRule, IPBlock, etc are derived from the
ProfitBricksService object, but there is no connection between them.
pylint complains:

__init__ method from base class 'ProfitBricksService' is not called

Calling the __init__ method from the base class is not wanted, because
the ProfitBricksService takes all the credentials for connecting with
the API. Thus make them normal objects.

profitbricks/profitbricks-sdk-python,StackPointCloud/profitbricks-sdk-python