Add crew designator to events

Distinguish between events for attendees to see and events that are
meant only for the crew.

shared/types/schedule.d.ts

@@ -1,6 +1,7 @@
 export interface ScheduleEvent {
 	name: string,
 	id: string,
+	crew?: boolean,
 	host?: string,
 	cancelled?: boolean,
 	description?: string,