Feature request: ability to switch to fullscreen clock mode when all alerts are disabled

[zibra]

Currently if I disable all alerts, button next to the snooze slider disappears. I was not able to find any other place to enable this clock mode.

[dhermanns]

Right now the needed Button is removed if alarms have been completely disabled. So the target Button has to be kept in a z-Layer above the "Snooze" Button.