Make object enter or leave maintenance mode, immediately or on schedule

Without time fields, immediately changes object maintenance state according to the "maintenance" field. If "startTime" and/or "endTime" is provided, maintenance is scheduled instead by creating one-time scheduled tasks (visible in scheduled task list and cancellable via the scheduled tasks API):

• startTime + endTime - schedule maintenance window (enter at startTime, leave at endTime);
• startTime only - schedule maintenance entry, leave manually;
• endTime only - schedule maintenance exit; combined with "maintenance": true the object enters maintenance immediately and leaves at endTime. If "schedule" is provided, a recurring maintenance window is scheduled instead: a recurrent scheduled task enters maintenance mode each time the cron expression matches, and maintenance mode is left automatically after "duration" minutes (required in this form). Other time fields are ignored in this form. Scheduling requires the "schedule object maintenance" system access right.