[Documentation]: /upsert docs don't clarify that at least one of version or config is required

[tariqksoliman]

The /upsert documentation (docs/pages/APIs/Configure/Configure_REST_API.md) marks both version and config as optional, but at least one must be provided. If neither is supplied, configJSON is undefined and the request crashes. The docs (and OpenAPI spec at docs/mmgis-openapi.json) should clarify this mutual dependency.

From #333