Convert Stack to separate action/status

Next and hopefully final step in decoupling action/status

This adjusts the Stack DB columns, model and class to be consistent with
Event/Resource, and split action/status.  This also modifies the both
APIs to join the action/status to avoid changing the API

Change-Id: Ifbdf254c62cad271b775b88de5b873f4e0b6d736
Introduce a schema for attributes

Similar to properties, adds attribute_schema and attributes members to
Resources in order to facilitate document generation and template
provider stubs for resources.

Change-Id: I5e207360816fbc685c66db68a7fab8afad11bf10
Implements: blueprint attributes-schema
Merge "Convert Stack to separate action/status"
Merge "Introduce a schema for attributes"