Stream API documentation

@BartVermeersch yes, in fact Stream will be GA before we will have APIs. They will be available sometime after GA (no timelines yet, but its high on our priority list for post GA).

In the meantime, Office 365 Video would continue to work. We will be giving Office 365 Admins control on when you want to move to Stream. If you need APIs you can wait before anything changes for your org.