Choose what field is used to save popup state

[glazou]

Reported on GeoNet, Map Journal use the primary ID field of a layer (OBJECTID, OID, FID) to know what popup has to be open through Main Stage Actions (or section configuration) and in certain data workflow update those values can change and break the popup configuration.

It would be great for author to be able to choose what field is used or to document how to publish a Feature Service that declare another field as it's primary ID.