feat(workflow) [SD-1214] Instances of actions for states

@amagdas @mugurrus @ioanpocol 

Here we have implemented the list of states in WorkflowStates and list of actions in WorkflowActions.

WorkflowStates behave like the enumerator for the available states in the system. Instead of writing the state names everywhere we wanted to have the list.

It is the same for the WorkflowActions. On resource level we still register the actions with the name, list of included/excluded states and privileges.

One thing we'd like to have a good level of "decoupling" between resources and states. For other domains (than AAP) this structure should be reasonably easy to configure to have:
* A different set of states
* A different set of actions between states
* Different set of privileges
* Different privilege-action settings

Please let us know what you think?