Recurring activities

[SilasPeters]

It should be possible to mark an activity as 'recurring' or 'repeated'. This is useful for activities like the weekly drinks.

At the very least it should be possible to repeat it weekly. If we feel like perfectionists, we could also make it as complicated as in the Google calendar or alarms page. Just follow the conventions.

@SanderHageman 's idea was to display them through a separate view or as a top bar in the activities overview. Another idea might be to add text at the activity tile, which indicates that it's recurring. Only the next repetition, or every repetition within a week, are displayed as normal in the activities overview (but with that bold text).

[SilasPeters]

It might be better to wait with implementing this feature after having separated the activities from koala, as suggested in ReIgnIT. This feature is quite impactful