Handle PATCH request for schedules

Currently, updating a schedule requires a JSON object and will expect solutions if the changes result in conflicts.

We should handle PATCH request when updating a schedule doesn’t generate new timeslots:

• setting lastDate when it was not set before, or changing it to a date before the previous one. This would delete timeslots for the schedule after lastDate.
• setting or changing defaultPlaylistId,
• setting or changing isRepetition.