Uptime Scheduled Maintenance

### Problem Statement

Applications monitored by uptime can have recurring periods of maintenance where their services would experience a downtime. However, uptime monitoring does not currently provide a way to configure these expected periods of downtime. This causes downtime issues to be created when maintenance starts.

### Solution Brainstorm

Provide a way to schedule these maintenance periods, automatically muting and unmuting the monitor.

### Product Area

Crons

Start by investigating the Crons product area and the existing uptime monitoring behavior that creates downtime issues during maintenance. Define how recurring maintenance periods should schedule automatic muting and unmuting, then verify that expected downtime no longer creates issues while monitoring resumes afterward.

Written by the indexing model from the issue text.