[Request] Customizable reminder timing

[FFdhorkin]

The current version sends out a reminder 5 minutes before an event. My workplace is currently needing to modify this by hand to be 1 minute before as a reminder, since some people have a tendency to be focused and forget while they do something else during that 5 minute window.

Ideally, though, this could be customizable per user. And maybe a user could get multiple reminders.

For example, I'd prefer 5 minute reminders to 1 minute reminders (but management wants 1m). But if I could get both 5m and 1m reminders, that would be even better (for me)! But I suspect most of my coworkers would only want one reminder, not multiple.

For simplicity, this could be specified by user as something like 1|5|10 or 10 or 1|5 with a single text box.