alarm-notify: Add "until start time" as predefined snooze time
Alerts may be triggered at varying times before the event starts (depending on the event configuration). An option to snooze reminders until event start time would be very convenient.
Without this option the default snooze time gets changed when a different option is chosen from the list of snooze times, which is inconvenient and requires extra clicks on next alert.
Edited by Milan Crha