This commit is going to be squashed into:
  ERP5Workflow: DC Workflows are now ERP5 objects (!1378).
  ERP5Workflow: Migrate all DCWorkflows to ERP5 objects (!1378).

Worklist filter objects based on given criterions and thus it makes more sense
for a Worklist to be a Predicate (albeit a Predicate with only Identity Criterion
and nothing else).

Criterion Properties:
  * State Variable.
  * local_roles (SECURITY_PARAMETER_ID): No more ad-hoc check_roles parameter on checkGuard().
  * Any Workflow Variable with for_catalog == 1.
  * Introduce getIdentityCriterionDict()

Also:
  * Remove "ad-hoc" matched* properties: This sounds like a premature optimization.
  * No need for Worklist Variable as these use "normal" Workflow Variables (where for_catalog == 1).