[Feature Request] Beep schedule

[acornforth]

I find the beep on the hour feature very handy to mark the passage of time at my desk, but i'd like to switch it off the rest of the time. Would be nice to set a schedule for when the beep is enabled.

I have a proposed implementation that would avoid cluttering the settings too, itsy cal could use calendar events to track when beep should be enabled.

I don't have lots of spare time at the moment, but would be willing to make a PR if the maintainers are open to contributions of this sort...