Fix: factorize mocks
Fix: domain mock functions args/kwargs handling
Fix: InvalidCredentialsError subject to unwanted side-effects
Add: domain querysets tests
Add: workflow type model tests
Fix: missing domain in to_WorkflowExecution call
Fix: Event and History models documentation
Add: WorkflowExecution model tests
Update : move event history mocking it's own submodule
Add: Event and History models tests
Add: tests for BaseWorkflowQuerySet and WorkflowTypeQuerySet
Add: WorkflowQuerySet tests