Calendar app: give the opportunity to disable reminder snooze

Summary

Add an option to disable snoozing in /e/OS Calendar

Description

What is the current behavior?

There is no option to disable snoozing in /e/OS Calendar, only an option to set the snooze delay.

What is the improved behavior?

In the screen (Settings > General settings > Default snooze delay time, see screenshot below) where the user can set the snooze delay, add an option None at the beginning. Make sure the snooze button doesn't appear on an event when this choice is selected.

What does it bring?

More consistency and more liberty for the user.

Mock-ups

Examples

Validation