Add "external user create/update" endpoint to the Identity Pro module #10354
We have some assumptions and should be configured in the external auth server side:
- UserId should always be GUID.
- Username and Email should not be in use by a different userid in our localdb, otherwise it all fails.
- If TenantId is in claims, then we should have the related tenant in the local database - we can skip this part for now, because we haven't made a tenant integration yet.
- Roles of the user may not be defined in our system. We assume that its responsibility of the admin to manage the synchronization manually for now.