Investigate whether timers can send notificaitons to lock screen

[blackjackshellac]

If the screen locks the timer notifications don't get sent/played until the user logs in again. Two things to look into,

• play the alarm sound at its specified time
• lock screen notifications in gnome shell?

[blackjackshellac]

Notifications will now play a sound in lock screen, and can display a notification is Lock Screen notifications are enabled.