- base_attributes_schema was added for base resource class.
- 'show' attribute was added to base_attributes_schema.
- fixed corresponding unittests
- definition of 'show' attribute was deleted from some resources,
because now it's presented in base resource class.
- Also was added temporary hook for stack_resource class to stop
resolving 'show' attribute.
Change-Id: Ie07fdc28a98be72064692ebffaf6d0c3eb128887