SDK/API should return `scheduled` flag for easy manipulation

When fetching content entries using SDK or API, the scheduled content is also returned with the published flag having a value of published. It will be great if we have a new flag scheduled=true or the published flag has a value of scheduled , or something on the similar lines.

This will make it easy to manipulate content without having to convert startDate and endDate to decide whether a content entry is worth sending to the UI.