A governance, compliance, security, or temporal policy constraint.
@type policy_type() :: :sod | :bod | :sla | :mandatory | :forbidden | :cardinality | :custom
@type t() :: %Ex4pmCore.ProcessIR.Policy{ description: String.t(), id: String.t(), metadata: map(), rules: map(), target_activities: [String.t()], target_objects: [String.t()], type: policy_type() }