Clarify Handling of Status

Review how Status is handled from External Identities when mapping into a Person Record.

1. Backends are able to assert select statuses, as per ExternalIdentityStatusEnum, on both External Identities and External Identity Roles.
   1. No recalculation on the External Identity is performed.
2. For add operations, Person Role status starts at Pending. For update operations, Person Role status is untouched until processed later.
3. At the end of the Pipeline, Person Role status is mapped from the External Identity Role status.
   1. If there is a conflict between the asserted status and provided validity dates, validity dates take precedence.  No conflict is possible because the relevant status options cannot be asserted directly.
4. Person status should be auto-recalculated at the end of the Pipeline, as per the usual recalculation rules. (See PipelinesTable::updatePersonStatus)
   1. Unless the Person is already Locked
5. Consider adding a new "sync_status" to replace the former OrgIdentity status.
6. Document, including any ARs, as needed.