Command Schedule using named Daypart

[alexharrington]

We encourage users to make a daypart to set the active hours for a given display.

It makes logical sense to use that same daypart to control screen power - so if it needs to change it can all be done in one place.

When scheduling a command, it would be nice if you could select a named daypart, and choose the start or end of the daypart to run your command.

Even nicer would be if you select a named daypart, you can set a command to be run at the start and a different command to be run at the end (or no command in either case). That way a single schedule could take care of screen power control, based on the daypart defined for that displays active hours.

[dasgarner]

I think most of the heavy lifting here happens in XMDS schedule, such that when a command event type is detected, it creates a schedule node for the start date and a schedule node for the end date (the end date of the event would be the start date of the node as that is what the player uses to determine when to run the command), depending on whether a command is set for one or both. This would mean we can implement without player changes, because the player still sees the same point-in-time commands it already expects.

We would also need an endCommandId as well as the existing commandId on the schedule object itself, and an additional field on the form to accommodate that.