Default reminder time

[murilopereirame]

As user i want to be able to configure a default reminder time so that whenever i create a new event this reminder is configured.

Duplicate of #1591

AC

• There is a setting to configure the default reminder time
• The default value is "no reminder"
• The setting value is used whenever a new event is created.
• The setting is synchronized across all devices.

Test notes

• [ ] Reminders still working
• [ ] User can create and edit a calendar with multiple default reminders
• [ ] Default reminders field shouldn't appear for creating, editing or accepting shared calendars
• [ ] When creating or editing an event, changing the calendar also set the event reminders
• [ ] The user can add reminders during event creation as normal
• [ ] When selecting a calendar, if it has default reminders, it'll overwrite the previous created reminders
• [ ] When editing an event, if the event had reminders, the editor will not load calendar's default reminders
• [ ] When editing an event, if the event has no reminders, no predefined reminder will be shown
• [ ] When creating an event, the editor will load calendar's default reminders
• [ ] Events invites works as expected