FEAT: goal reminder

[firedotguy]

Add goals reminder in notification.

When i set up goal, i should been able to turn on reminders, add time to remind (static time or after specific acrivity), add comment (eg. Dont forget to do sports!). In notification will be available 3 buttons - start activity, postpone (postpone time can edit in settings) and cancel (if i press on this button notificarion removes)

Also maybe add limit reminders, eg "you will reach limit in 10 mins!"